aac: mp4ff include fix
use pkgconfig for libzip
artwork: added configure option to build artwork without network support
mpgmad: optimize frame syncing by reducing number of backward seeks
vfs_zip: added cache for optimizing small reads and backward-seeks
gtkui: ported seekbar to widget system
gtkui: ported playback controls toolbar to widget system
gtkui: ported volumebar to widget system
lastfm: change mbid to musicbrainz_trackid
gtkui: get rid of top bar in favor of design mode widgets
gtkui: fixed bogus lookup_widget("volumebar") calls