Re-license almost all the playback modules to LGPLv2.1+ with
authorization from their respective contributors (230+)

This includes:
 - access, codec, packetizers, demux
 - audio filters, audio mixers, audio output
 - video filters, video chroma, video output
 - text renderers
 - XML parser
 - ARM NEON and SSE2 optimisations (mostly for chromas and filters)

Some modules are not concerned:
 - BDA and DShow access modules because Manol Manolov is AWOL
 - Real RTSP, because it is derived from Xine
 - x264 and t140 because they are encoders only
 - DLL Loader, because it is derived from MPlayer
 - DTS packetizer, because Jon Lech Johansen is AWOL
 - Shine and WMAfixed, because they are derived from Rockbox
 - Real demuxer, as it is derived from MPlayer and Wang Bo is AWOL
 - MPC demuxer, as Yavor Doganov is AWOL
 - Tivo demuxer, because it is derived from an MPlayer fork
 - Playlist demuxer, (WPL and ZPL parts missing), because suheaven is AWOL
 - iOS audio output and video display, because author refus...