layers.txt: meta-xilinx has moved

Signed-off-by: Koen Kooi <koen@dominion.thruhere.net>
layerman: switch meta-beagle to 'danny'

Signed-off-by: Koen Kooi <koen@dominion.thruhere.net>
Merge remote-tracking branch 'origin/angstrom-v2012.12-yocto1.3'