Added DS1307 realtime clock support

Signed-off-by: Stephan Raue <stephan@openelec.tv>
xbmc: eep old repo content if update fails

should fix empty repos
Python: force disable bluetooth support

closes #2575
Merge remote-tracking branch 'upstream/master' into openelec-systemd

Conflicts:
	projects/RPi/linux/linux.arm.conf