layers.txt: !!! upgrade layers to current master !!!

* default webOS-ports builds are still from master, if you want to stay
  with danny, change BRANCH_COMMON back to "danny" and call "make update"

Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>
layers.txt: Initial setup for Tofee repository

Signed-off-by: Christophe Chapuis <chris.chapuis@gmail.com>
bblayers.conf: add meta-acer layer

Signed-off-by: Christophe Chapuis <chris.chapuis@gmail.com>
setup-env: set MACHINE=a500 by default

Signed-off-by: Christophe Chapuis <chris.chapuis@gmail.com>