[Azoth Sarin] Tox key isn't settable, just store tox state.
[Azoth Sarin] Tox instance is a member variable now.
[Azoth Sarin] Persistent Tox state.
[Azoth Sarin] GetToxAddress().
[Azoth Sarin] GetToxAddress() should be in local anon ns.
[Azoth Sarin] ToxThread::GetToxId().