layers.txt: bump bitbake, oe-core, meta-oe, meta-qt5 revisions a bit

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>
setup-env: set MACHINE=a500 by default

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