ALLJOYN-1575 Fix crash in LocalEndpoint::AlarmTriggered due to deleted ReplyContext

Change-Id: I9414181a52cd541e1dbcbb4d2008b127d8b1271f
ALLJOYN-1950 NullEndpoint::PushMessage must convert error codes other than ER_STOPPING_THREAD into ER_OK
to resemble the behavior of RemoteEndpoint.
If RegisterReplyHandler fails, ProxyBusObject::MethodCall does not need to unregister the reply handler.

Change-Id: Ic0924e2d812e747d7f9b8b4539ca0fe895e930e9
ALLJOYN-1847: Added sessionless signal catchup feature for AJ clients using the same daemon

Change-Id: I65a1b93e74080d637de6ea568a649f18130bbc60