Log Message:
audio/termusic: update to 0.6.6

-New: add all key configuration for global, library and playlist(huge work).
-Minor Fix: Don't close search dialogue after add to playlist.
-New: new player backend mpv. If you prefer mpv, you can build with feature
 gate mpv. My testing result: gstreamer doesn't work for ape file, mpv works
 for everything but flac may seem buggy.