Add mpv to default players
Add mpv to default players

It's another fork of mplayer, more active than mplayer2.

sputnick-dev/weboob,frankrousseau/weboob,yannrouillard/weboob,willprice/weboob,Konubinix/weboob,willprice/weboob,Boussadia/weboob,RouxRC/weboob,Boussadia/weboob,nojhan/weboob-devel,sputnick-dev/weboob,nojhan/weboob-devel,sputnick-dev/weboob,yannrouillard/weboob,RouxRC/weboob,willprice/weboob,laurent-george/weboob,nojhan/weboob-devel,laurent-george/weboob,frankrousseau/weboob,Boussadia/weboob,Konubinix/weboob,RouxRC/weboob,Konubinix/weboob,laurent-george/weboob,Boussadia/weboob,frankrousseau/weboob,yannrouillard/weboob