added PG for billboard testing

src/Mesh/babylon.abstractMesh.ts

@@ -874,7 +874,7 @@
                 this.parent.getWorldMatrix().multiplyToRef(this._meshToBoneReferal.getWorldMatrix(), completeMeshReferalMatrix);
             }
 
-            // Billboarding
+            // Billboarding (testing PG:http://www.babylonjs-playground.com/#UJEIL#13)
             if (this.billboardMode !== AbstractMesh.BILLBOARDMODE_NONE && this.getScene().activeCamera) {
                 if ((this.billboardMode & AbstractMesh.BILLBOARDMODE_ALL) !== AbstractMesh.BILLBOARDMODE_ALL) {
                     // Need to decompose each rotation here