gettext: update to gettext-0.18.3.2

Signed-off-by: Stephan Raue <stephan@openelec.tv>
new package: readd package 'ffmpeg'

Signed-off-by: Stephan Raue <stephan@openelec.tv>
new package: add package 'xbmc-master'

Signed-off-by: Stephan Raue <stephan@openelec.tv>
projects/*/options: add support to build XBMC (master) with 'PROJECT=xyz ARCH=xyz XBMC=master make'

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