Fix issue that prevented attachments from working when using share sheet
Fix issue that prevented attachments from working when using share sheet

The activity item that’s used in the share sheet uses an internal proxy
delegate that proxies the AHADropDelegate methods to another object. This
proxy delegate didn’t implement the -renderAttachmentForPiece:completion:
method, and thus it was not possible to provide an attachment when using
the share sheet method of dropping.

allihoopa/Allihoopa-iOS