Moved most of functionality of bin/bitbake to lib/bb/main.py
to be able to call bitbake from python code.
(Bitbake rev: d377f7f88d73f4e5d2dffef03d6acee809827ac6)
Signed-off-by: Ed Bartosh <ed.bartosh@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>