fix Freeboard#60: merged ducksboard/gridster.js@021a6c2

Author: Zbigniew Zasieczny

lib/js/thirdparty/jquery.gridster.js

@@ -1,6 +1,7 @@
 /*! gridster.js - v0.1.0 - 2013-06-14
  * http://gridster.net/
- * Copyright (c) 2013 ducksboard; Licensed MIT */
+ * Copyright (c) 2013 ducksboard; Licensed MIT
+ * 2015-08-12: merged https://github.com/ducksboard/gridster.js/commit/021a6c23e851210c1b817bd353a1e5e19ce10b90 to fix dragging issue in Chrome */
 
 ;
 (function($, window, document, undefined)
@@ -444,9 +445,9 @@
 	var $window = $(window);
 	var isTouch = !!('ontouchstart' in window);
 	var pointer_events = {
-		start: isTouch ? 'touchstart.gridster-draggable' : 'mousedown.gridster-draggable',
-		move : isTouch ? 'touchmove.gridster-draggable' : 'mousemove.gridster-draggable',
-		end  : isTouch ? 'touchend.gridster-draggable' : 'mouseup.gridster-draggable'
+        start: 'touchstart.gridster-draggable mousedown.gridster-draggable',
+        move: 'touchmove.gridster-draggable mousemove.gridster-draggable',
+        end: 'touchend.gridster-draggable mouseup.gridster-draggable'
 	};
 
 	/**
@@ -533,7 +534,7 @@
 
 	fn.get_mouse_pos = function(e)
 	{
-		if(isTouch)
+		if (e.originalEvent && e.originalEvent.touches)
 		{
 			var oe = e.originalEvent;
 			e = oe.touches.length ? oe.touches[0] : oe.changedTouches[0];