xbmc: new package

XBMC is an award-winning free and open source (GPL) software media player and
entertainment hub for digital media.
This package was originally found at : https://github.com/huceke/buildroot-rbp
By gimli <ebsi4711@gmail.com>

Signed-off-by: Maxime Hadjinlian <maxime.hadjinlian@gmail.com>