Added a brief explanation of this temporary directory to the chapter
that presents the structure of the Source Directory. The
explanation is based on Paul Eggleton's input.
(From yocto-docs rev: 688c36aec57bb283d03ffb7e1d9448563cb1496c)
Signed-off-by: Scott Rifenbark <scott.m.rifenbark@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>