Add dataAttr option for items. (#702)

Closes #590 
Closes #591

Author: bbrala

dist/jquery.contextMenu.css

@@ -12,7 +12,7 @@
  * Licensed under
  *   MIT License http://www.opensource.org/licenses/mit-license
  *
- * Date: 2019-10-05T08:37:44.295Z
+ * Date: 2019-10-06T14:19:04.540Z
  */
 @-webkit-keyframes cm-spin {
   0% {

dist/jquery.contextMenu.js

@@ -11,7 +11,7 @@
  * Licensed under
  *   MIT License http://www.opensource.org/licenses/mit-license
  *
- * Date: 2019-10-05T08:37:44.262Z
+ * Date: 2019-10-06T14:19:04.506Z
  */
 
 // jscs:disable
@@ -1121,6 +1121,11 @@
                     'contextMenu': opt,
                     'contextMenuRoot': root
                 });
+                if(opt.dataAttr){
+                    $.each(opt.dataAttr, function (key, item) {
+                        opt.$menu.attr('data-' + opt.key, item);
+                    });
+                }
 
                 $.each(['callbacks', 'commands', 'inputs'], function (i, k) {
                     opt[k] = {};