Implement the playback event handling as a system-wide multi-purpose event system. Unified mpeg.c and playback.c audio event handling. Converted ata_idle_notify to use the new event handling system also.

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@16682 a1c6a512-1295-4272-9138-f99709370657
14 files changed