make vector constructor arguments optional

dist/preview release/what's new.md

@@ -52,6 +52,7 @@
 - Added poster property on VideoTexture ([sebavan](http://www.github.com/sebavan))
 - Added ```onUserActionRequestedObservable``` to workaround and detect autoplay video policy restriction on VideoTexture ([sebavan](http://www.github.com/sebavan))
 - `Sound` now accepts `MediaStream` as source to enable easier WebAudio and WebRTC integrations ([menduz](https://github.com/menduz))
+- Vector x, y and z constructor parameters are now optional and default to 0 ([TrevorDev](https://github.com/TrevorDev))
 
 ### glTF Loader
 

src/Math/babylon.math.ts

@@ -869,9 +869,9 @@
          */
         constructor(
             /** defines the first coordinate */
-            public x: number, 
+            public x: number = 0, 
             /** defines the second coordinate */
-            public y: number) {
+            public y: number = 0) {
         }
 
         /**
@@ -1496,15 +1496,15 @@
             /**
              * Defines the first coordinates (on X axis)
              */
-            public x: number,
+            public x: number = 0,
             /**
              * Defines the second coordinates (on Y axis)
              */
-            public y: number,
+            public y: number = 0,
             /**
              * Defines the third coordinates (on Z axis)
              */
-            public z: number
+            public z: number = 0
         ) {
         }