Texture.toJSON(): flipY support.

src/loaders/ObjectLoader.js

@@ -401,6 +401,8 @@ Object.assign( THREE.ObjectLoader.prototype, {
 
 				}
 
+				if ( data.flipY !== undefined ) texture.flipY = data.flipY;
+
 				textures[ data.uuid ] = texture;
 
 			}

src/textures/Texture.js

@@ -155,7 +155,9 @@ THREE.Texture.prototype = {
 
 			minFilter: this.minFilter,
 			magFilter: this.magFilter,
-			anisotropy: this.anisotropy
+			anisotropy: this.anisotropy,
+
+			flipY: this.flipY
 		};
 
 		if ( this.image !== undefined ) {