Fixed #107: allow repeating select event

docs/timeline.html

@@ -820,6 +820,7 @@ timeline.off('select', onSelect);
   <tr>
     <td>select</td>
     <td>Fired after the user selects or deselects items by tapping or holding them.
+      When a use taps an already selected item, the select event is fired again.
       Not fired when the method <code>setSelection</code>is executed.
     </td>
     <td>

src/timeline/Timeline.js

@@ -633,8 +633,9 @@ Timeline.prototype._onSelectItem = function (event) {
 
   var newSelection = this.getSelection();
 
-  // if selection is changed, emit a select event
-  if (!util.equalArray(oldSelection, newSelection)) {
+  // emit a select event,
+  // except when old selection is empty and new selection is still empty
+  if (newSelection.length > 0 || oldSelection.length > 0) {
     this.emit('select', {
       items: this.getSelection()
     });