item-handle in isolate scope issue fix

[Ahhhhmed]

I had an issue with as-sortable-item-handle being in a isolate scope and having no access to as-sortable-item scope. I fixed the issue, but this fix is not so pretty.

You can suggest a better way to design the fix if you have a better idea.

[bars3s]

Looks like it was fixed here https://github.com/a5hik/ng-sortable/issues/93 but have not been merged yet