restore 'empty' drag algorithm

src/DragAndDrop.js

@@ -27,7 +27,6 @@
                         Math.abs(pos.x - dd.startPointerPos.x),
                         Math.abs(pos.y - dd.startPointerPos.y)
                     );
-
                     if (distance < dragDistance) {
                         return;
                     }
@@ -138,11 +137,10 @@
         if(dbf !== undefined) {
             newNodePos = dbf.call(this, newNodePos, evt);
         }
-
         this.setAbsolutePosition(newNodePos);
 
-        if (this._lastPos && this._lastPos.x === newNodePos.x &&
-            this._lastPos.y === newNodePos.y) {
+        if (!this._lastPos || this._lastPos.x !== newNodePos.x ||
+            this._lastPos.y !== newNodePos.y) {
             dd.anim.dirty = true;
         }
 

src/Global.js

@@ -235,6 +235,10 @@ var Kinetic = {};
          * @param {Object} config
          * @param {Boolean} [config.clearBeforeDraw] set this property to false if you don't want
          * to clear the canvas before each layer draw.  The default value is true.
+         * @param {Boolean} [config.visible]
+         * @param {String} [config.id] unique id
+         * @param {String} [config.name] non-unique name
+         * @param {Number} [config.opacity] determines node opacity.  Can be any number between 0 and 1
          * @@containerParams
          * @example
          * var layer = new Kinetic.FastLayer();