Remove Handler usage from AndroidAsync.

This belongs in a higher level library, like ion.

Change-Id: Ide95cc25db257819eda1d93fb8892c21158026db
Change HashList behavior.

Do not automatically remove the entry/tag if the last item is removed.

Change-Id: I5c8fe8ccc51cb6e3ae0a49ceb1f80fa0dbe0cb6c