Merge pull request #63 from ericbarnes/tags-tab

Adding tab support for tags

select2.js

@@ -1123,6 +1123,7 @@
                         killEvent(e);
                         return;
                     case KEY.ENTER:
+                    case KEY.TAB:
                         this.selectHighlighted();
                         killEvent(e);
                         return;