CC-4607: Library: Please make the 'Add x items' following mouse's point

-fixed

airtime_mvc/public/js/airtime/library/events/library_playlistbuilder.js

@@ -102,6 +102,10 @@ var AIRTIME = (function(AIRTIME) {
                         return container;
                     },
                     cursor : 'pointer',
+                    cursorAt: {
+                        top: 30,
+                        left: 100
+                    },
                     connectToSortable : '#spl_sortable'
                 });
     };