ScreenshotTools. Implementation usage of interface IScreenshotSize

Added async methods support
> https://forum.babylonjs.com/t/define-typescript-interface-for-options-of-method-to-make-screenshots/4713

src/Misc/tools.ts

@@ -774,7 +774,7 @@ export class Tools {
      * @returns screenshot as a string of base64-encoded characters. This string can be assigned
      * to the src parameter of an <img> to display it
      */
-    public static CreateScreenshotAsync(engine: Engine, camera: Camera, size: any, mimeType: string = "image/png"): Promise<string> {
+    public static CreateScreenshotAsync(engine: Engine, camera: Camera, size: IScreenshotSize | number, mimeType: string = "image/png"): Promise<string> {
         throw _DevTools.WarnImport("ScreenshotTools");
     }
 
@@ -819,7 +819,7 @@ export class Tools {
      * @returns screenshot as a string of base64-encoded characters. This string can be assigned
      * to the src parameter of an <img> to display it
      */
-    public static CreateScreenshotUsingRenderTargetAsync(engine: Engine, camera: Camera, size: any, mimeType: string = "image/png", samples: number = 1, antialiasing: boolean = false, fileName?: string): Promise<string> {
+    public static CreateScreenshotUsingRenderTargetAsync(engine: Engine, camera: Camera, size: IScreenshotSize | number, mimeType: string = "image/png", samples: number = 1, antialiasing: boolean = false, fileName?: string): Promise<string> {
         throw _DevTools.WarnImport("ScreenshotTools");
     }