Add a new API in command.py to get the cpu count in order to set the appropriate default BB_NUMBER_THREADS and PARALLEL_MAKE variables.
(Bitbake rev: 335047b2e440e65713e88fabb24b47a9c82f939b)
Signed-off-by: Shane Wang <shane.wang@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>