List item leave and checked animations with promises
 * list item directive optionally requires list directive
 * register and unregister editor closed callback when list item is opened in editor
 * removed data binding from task checkbox and call taskChecked in editor to update correct values into list
 * added initial max-height to .animate-list-item-leave to make max-height animation working in iOS.
 * use track by in list item ng-repeat
 * fool UI with programmatically set class in leave item promise to display checkbox as checked when returning from editor where item checkbox was checked
 * checkbox checked with animation