Making Sprite2d a Transparent kind of Render Mode.

Adding the zOrder optional parameter for primitive construction. (MasterK will be happy!)

src/Canvas2d/babylon.ellipse2d.ts

@@ -215,6 +215,7 @@
          * - rotation: the initial rotation (in radian) of the primitive. default is 0
          * - scale: the initial scale of the primitive. default is 1. You can alternatively use scaleX &| scaleY to apply non uniform scale
          * - opacity: set the overall opacity of the primitive, 1 to be opaque (default), less than 1 to be transparent.
+         * - zOrder: override the zOrder with the specified value
          * - origin: define the normalized origin point location, default [0.5;0.5]
          * - size: the size of the group. Alternatively the width and height properties can be set. Default will be [10;10].
          * - subdivision: the number of subdivision to create the ellipse perimeter, default is 64.
@@ -250,6 +251,7 @@
             scaleX            ?: number,
             scaleY            ?: number,
             opacity           ?: number,
+            zOrder            ?: number, 
             origin            ?: Vector2,
             size              ?: Size,
             width             ?: number,

src/Canvas2d/babylon.group2d.ts

@@ -36,6 +36,7 @@
          * - rotation: the initial rotation (in radian) of the primitive. default is 0
          * - scale: the initial scale of the primitive. default is 1. You can alternatively use scaleX &| scaleY to apply non uniform scale
          * - opacity: set the overall opacity of the primitive, 1 to be opaque (default), less than 1 to be transparent.
+         * - zOrder: override the zOrder with the specified value
          * - origin: define the normalized origin point location, default [0.5;0.5]
          * - size: the size of the group. Alternatively the width and height properties can be set. If null the size will be computed from its content, default is null.
          *  - cacheBehavior: Define how the group should behave regarding the Canvas's cache strategy, default is Group2D.GROUPCACHEBEHAVIOR_FOLLOWCACHESTRATEGY
@@ -69,6 +70,7 @@
             scaleY            ?: number,
             trackNode         ?: Node,
             opacity           ?: number,
+            zOrder            ?: number, 
             origin            ?: Vector2,
             size              ?: Size,
             width             ?: number,

src/Canvas2d/babylon.lines2d.ts

@@ -382,6 +382,7 @@
          * - rotation: the initial rotation (in radian) of the primitive. default is 0
          * - scale: the initial scale of the primitive. default is 1. You can alternatively use scaleX &| scaleY to apply non uniform scale
          * - opacity: set the overall opacity of the primitive, 1 to be opaque (default), less than 1 to be transparent.
+         * - zOrder: override the zOrder with the specified value
          * - origin: define the normalized origin point location, default [0.5;0.5]
          * - fillThickness: the thickness of the fill part of the line, can be null to draw nothing (but a border brush must be given), default is 1.
          * - closed: if false the lines are said to be opened, the first point and the latest DON'T connect. if true the lines are said to be closed, the first and last point will be connected by a line. For instance you can define the 4 points of a rectangle, if you set closed to true a 4 edges rectangle will be drawn. If you set false, only three edges will be drawn, the edge formed by the first and last point won't exist. Default is false.
@@ -419,6 +420,7 @@
             scaleX            ?: number,
             scaleY            ?: number,
             opacity           ?: number,
+            zOrder            ?: number, 
             origin            ?: Vector2,
             fillThickness     ?: number,
             closed            ?: boolean,

src/Canvas2d/babylon.prim2dBase.ts

@@ -1294,34 +1294,35 @@
         public  static _bigInt = Math.pow(2, 30);
 
         constructor(settings: {
-            parent?: Prim2DBase,
-            id?: string,
-            children?: Array<Prim2DBase>,
-            position?: Vector2,
-            x?: number,
-            y?: number,
-            rotation?: number,
-            scale?: number,
-            scaleX?: number,
-            scaleY?: number,
-            opacity?: number,
-            origin?: Vector2,
-            layoutEngine?: LayoutEngineBase | string,
-            isVisible?: boolean,
+            parent            ?: Prim2DBase,
+            id                ?: string,
+            children          ?: Array<Prim2DBase>,
+            position          ?: Vector2,
+            x                 ?: number,
+            y                 ?: number,
+            rotation          ?: number,
+            scale             ?: number,
+            scaleX            ?: number,
+            scaleY            ?: number,
+            opacity           ?: number,
+            zOrder            ?: number, 
+            origin            ?: Vector2,
+            layoutEngine      ?: LayoutEngineBase | string,
+            isVisible         ?: boolean,
             childrenFlatZOrder?: boolean,
-            marginTop?: number | string,
-            marginLeft?: number | string,
-            marginRight?: number | string,
-            marginBottom?: number | string,
-            margin?: number | string,
-            marginHAlignment?: number,
-            marginVAlignment?: number,
-            marginAlignment?: string,
-            paddingTop?: number | string,
-            paddingLeft?: number | string,
-            paddingRight?: number | string,
-            paddingBottom?: number | string,
-            padding?: string,
+            marginTop         ?: number | string,
+            marginLeft        ?: number | string,
+            marginRight       ?: number | string,
+            marginBottom      ?: number | string,
+            margin            ?: number | string,
+            marginHAlignment  ?: number,
+            marginVAlignment  ?: number,
+            marginAlignment   ?: string,
+            paddingTop        ?: number | string,
+            paddingLeft       ?: number | string,
+            paddingRight      ?: number | string,
+            paddingBottom     ?: number | string,
+            padding           ?: string,
         }) {
 
             // Avoid checking every time if the object exists
@@ -1424,6 +1425,10 @@
                 }
             }
 
+            if (settings.zOrder != null) {
+                this.zOrder = settings.zOrder;
+            }
+
             // Set the model related properties
             if (settings.position != null) {
                 this.position = settings.position;

src/Canvas2d/babylon.rectangle2d.ts

@@ -300,6 +300,7 @@
          * - rotation: the initial rotation (in radian) of the primitive. default is 0
          * - scale: the initial scale of the primitive. default is 1. You can alternatively use scaleX &| scaleY to apply non uniform scale
          * - opacity: set the overall opacity of the primitive, 1 to be opaque (default), less than 1 to be transparent.
+         * - zOrder: override the zOrder with the specified value
          * - origin: define the normalized origin point location, default [0.5;0.5]
          * - size: the size of the group. Alternatively the width and height settings can be set. Default will be [10;10].
          * - roundRadius: if the rectangle has rounded corner, set their radius, default is 0 (to get a sharp edges rectangle).
@@ -334,6 +335,7 @@
             scaleX            ?: number,
             scaleY            ?: number,
             opacity           ?: number,
+            zOrder            ?: number, 
             origin            ?: Vector2,
             size              ?: Size,
             width             ?: number,

src/Canvas2d/babylon.sprite2d.ts

@@ -251,6 +251,7 @@
          * - rotation: the initial rotation (in radian) of the primitive. default is 0
          * - scale: the initial scale of the primitive. default is 1. You can alternatively use scaleX &| scaleY to apply non uniform scale
          * - opacity: set the overall opacity of the primitive, 1 to be opaque (default), less than 1 to be transparent.
+         * - zOrder: override the zOrder with the specified value
          * - origin: define the normalized origin point location, default [0.5;0.5]
          * - spriteSize: the size of the sprite (in pixels), if null the size of the given texture will be used, default is null.
          * - spriteLocation: the location (in pixels) in the texture of the top/left corner of the Sprite to display, default is null (0,0)
@@ -275,38 +276,39 @@
          */
         constructor(texture: Texture, settings?: {
 
-            parent?: Prim2DBase,
-            children?: Array<Prim2DBase>,
-            id?: string,
-            position?: Vector2,
-            x?: number,
-            y?: number,
-            rotation?: number,
-            scale?: number,
-            scaleX?: number,
-            scaleY?: number,
-            opacity?: number,
-            origin?: Vector2,
-            spriteSize?: Size,
-            spriteLocation?: Vector2,
-            spriteScaleFactor?: Vector2,
-            invertY?: boolean,
-            alignToPixel?: boolean,
-            isVisible?: boolean,
+            parent            ?: Prim2DBase,
+            children          ?: Array<Prim2DBase>,
+            id                ?: string,
+            position          ?: Vector2,
+            x                 ?: number,
+            y                 ?: number,
+            rotation          ?: number,
+            scale             ?: number,
+            scaleX            ?: number,
+            scaleY            ?: number,
+            opacity           ?: number,
+            zOrder            ?: number, 
+            origin            ?: Vector2,
+            spriteSize        ?: Size,
+            spriteLocation    ?: Vector2,
+            spriteScaleFactor ?: Vector2,
+            invertY           ?: boolean,
+            alignToPixel      ?: boolean,
+            isVisible         ?: boolean,
             childrenFlatZOrder?: boolean,
-            marginTop?: number | string,
-            marginLeft?: number | string,
-            marginRight?: number | string,
-            marginBottom?: number | string,
-            margin?: number | string,
-            marginHAlignment?: number,
-            marginVAlignment?: number,
-            marginAlignment?: string,
-            paddingTop?: number | string,
-            paddingLeft?: number | string,
-            paddingRight?: number | string,
-            paddingBottom?: number | string,
-            padding?: string,
+            marginTop         ?: number | string,
+            marginLeft        ?: number | string,
+            marginRight       ?: number | string,
+            marginBottom      ?: number | string,
+            margin            ?: number | string,
+            marginHAlignment  ?: number,
+            marginVAlignment  ?: number,
+            marginAlignment   ?: string,
+            paddingTop        ?: number | string,
+            paddingLeft       ?: number | string,
+            paddingRight      ?: number | string,
+            paddingBottom     ?: number | string,
+            padding           ?: string,
         }) {
 
             if (!settings) {
@@ -324,7 +326,7 @@
             this.spriteFrame = 0;
             this.invertY = (settings.invertY == null) ? false : settings.invertY;
             this.alignToPixel = (settings.alignToPixel == null) ? true : settings.alignToPixel;
-            this.isAlphaTest = true;
+            this.isTransparent = true;
 
             if (settings.spriteSize == null || !texture.isReady()) {
                 if (texture.isReady()) {

src/Canvas2d/babylon.text2d.ts

@@ -260,6 +260,7 @@
          * - rotation: the initial rotation (in radian) of the primitive. default is 0
          * - scale: the initial scale of the primitive. default is 1. You can alternatively use scaleX &| scaleY to apply non uniform scale
          * - opacity: set the overall opacity of the primitive, 1 to be opaque (default), less than 1 to be transparent.
+         * - zOrder: override the zOrder with the specified value
          * - origin: define the normalized origin point location, default [0.5;0.5]
          * - fontName: the name/size/style of the font to use, following the CSS notation. Default is "12pt Arial".
          * - fontSuperSample: if true the text will be rendered with a superSampled font (the font is twice the given size). Use this settings if the text lies in world space or if it's scaled in.
@@ -295,6 +296,7 @@
             scaleX            ?: number,
             scaleY            ?: number,
             opacity           ?: number,
+            zOrder            ?: number, 
             origin            ?: Vector2,
             fontName          ?: string,
             fontSuperSample   ?: boolean,