opusfile: USES=libtool

Adopt the recent porting rule of libtool usage.
Do not produce/install static libraries.
libbs2b: USES=libtool:keepla

Adopt the recent porting rule of libtool usage.
qmmp-0.7.7, qmmp-plugin-pack-0.7.7

Drop away GOOGLECODE hostage from package downloadable sites list.