Drop control - fix #2834 (#2974)

* Fix redraw order

* Fix error when option is not defined

* Allow template labels

* Add .travis.yml file

* Add experiment travis code

* Fix react example

* Add drop event info

docs/timeline/index.html

@@ -1562,6 +1562,16 @@ timeline.off('select', onSelect);
       </td>
     </tr>
 
+    <tr>
+      <td>drop</td>
+      <td>
+        Passes a properties object as returned by the method <a href="#getEventProperties"><code>Timeline.getEventProperties(event)</code></a>.
+      </td>
+      <td>Fired when dropping inside the Timeline.
+      </td>
+    </tr>
+
+
     <tr>
       <td>mouseOver</td>
       <td>

lib/timeline/Core.js

@@ -262,7 +262,7 @@ Core.prototype._create = function (container) {
       y: event.clientY
     }
     me.itemSet._onAddItem(event);
-
+    me.emit('drop', me.getEventProperties(event))
     return false;
   }