New method for checking the status of the working tree of a repository.
(From OE-Core rev: 4e5eea06a77eca7311209b0b650e79e816713ab9)
Signed-off-by: Markus Lehtonen <markus.lehtonen@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>