Remove empty destructor for AudioOutputGraph's Buffer class. It is derived from QByteArray which doesn't have a virtual destructor, so Buffer's destructor could never be called. Coverity 1228788
Move audiooutputgraph.* into audio/ where they belong.

A make distclean is recommended.
Whitespace fixes for mythnotification.h
Initialise m_id in MythNotification. Coverity 1228786