media-sound/rbutil: initial import

see http://git.overlays.gentoo.org/gitweb/?p=dev/xmw.git;a=tree;f=media-sound/rbutil;hb=HEAD
and https://bugs.gentoo.org/show_bug.cgi?id=183494
media-sound/rbutil: rename qt packages
media-plugins/audacious-plugins: remove ipv6 useflag

see https://github.com/audacious-media-player/audacious-plugins/commit/008c000d35ece8ca25bc3c3379d3c00d12de96c5
audacious-plugins & audacious: drop EGIT_BOOTSTRAP="autogen.sh"
app-emulation/playonlinux: version bump
media-plugins/audacious-plugins: add soxr useflag

see https://github.com/audacious-media-player/audacious-plugins/commit/7e941af8c87429b67f6b9310a5f17a07460e451f