Default media player settings

Hi,

I have added the ability to read the default player from a ~/.config/yt settings file, so the user doesn't have to specify omxplayer at the command line all the time.

I also added a "--player omxplayerlocal" option, to be able to send the audio output to the local (analog) output of the raspberry pi.

Please review and pull if you like.

Regards,

George