Add documentation and cleanup

src/js/components/ImageEditor/3dHandler.js

@@ -3,7 +3,6 @@
 function ThreeDHandler(canvas) {
     var _overlay = new fabric.Group();
     var _image;
-    var self = this;
 
     function init() {
         _overlay
@@ -22,16 +21,25 @@ function ThreeDHandler(canvas) {
 
     init();
 
+    /**
+     * @return {ThreeDHandler}
+     */
     this.disable = function () {
         _overlay.setVisible(false).canvas.renderAll();
         return this;
     };
 
+    /**
+     * @return {ThreeDHandler}
+     */
     this.enable = function () {
         _overlay.setVisible(true).canvas.renderAll();
         return this;
     };
 
+    /**
+     * @return {ThreeDHandler}
+     */
     this.setImage = function (img) {
         img.set({
             originX: 'center',