ffmpeg: change to official release

Signed-off-by: Stephan Raue <stephan@openelec.tv>
xbmc-master_ update to xbmc-master-14-687ac52, update FM patch, add patch to fix commit https://github.com/xbmc/xbmc/commit/6322457ea46e83491fa0675cb6ac9bf2e3578882

Signed-off-by: Stephan Raue <stephan@openelec.tv>
bcm2835-driver: update to bcm2835-driver-1e7d3d9

Signed-off-by: Stephan Raue <stephan@openelec.tv>
bcm2835-bootloader: update to bcm2835-bootloader-1e7d3d9

Signed-off-by: Stephan Raue <stephan@openelec.tv>
projects/RPi/patches/xbmc-master: update RPi support patch

Signed-off-by: Stephan Raue <stephan@openelec.tv>
linux: update to linux-3.15.4

Signed-off-by: Stephan Raue <stephan@openelec.tv>
xbmc-master: update to xbmc-master-14-dae6f76

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