ffmpeg: add some upstream patches

Signed-off-by: Stephan Raue <stephan@openelec.tv>
xbmc-pvr-addons: fix patch

Signed-off-by: Stephan Raue <stephan@openelec.tv>
Merge branch 'master' of github.com:OpenELEC/OpenELEC.tv
update CONTRIBUTING.md
ffmpeg: update to ffmpeg-1.2.3, sync upstream patches

Signed-off-by: Stephan Raue <stephan@openelec.tv>
Merge branch 'master' of github.com:OpenELEC/OpenELEC.tv
xbmc: update to xbmc-13.alpha-2ef8929

Signed-off-by: Stephan Raue <stephan@openelec.tv>
xbmc: update XVBA patch

Signed-off-by: Stephan Raue <stephan@openelec.tv>