Gpgtools Libmacgpg

[FIX] Releases the LPXTTask object when the GPGTaskHelper is dealloced [#134 state:fixed]

• If the GPGTaskHelper was still processing responses received by the XPC service while the LPXTTask was being dealloced, it was possible that the LPXTTask object still existed but the dispatch_queue used inside was already shutdown. This lead to a crash in the XPC service.
• There's no need to release the LPXTTask before the GPGTaskHelper is dealloced, so now the LPXTTask is released in the dealloc method. This way we can be sure, that all responses were already process when GPGTaskHelper is shutting down. https://github.com/GPGTools/Libmacgpg/commit/6b729d2649d154879b4007...