File inclusion and variable assignment tracking

This is the assignment/inclusion tracking stuff I've had floating around. In further testing, I found one missing [1] that made it fail for "bitbake -e [specific package]". Haven't had any other troubles with it.

This could totally use improvement, but I think this has reached a point where:
1. It's more useful to have it than not.
2. It will be better improved by feedback from live usage.

Impact outside of the bitbake -e case is basically nil, and in the -e case it's a HUGE improvement in usability.

The following changes since commit d316f28ed725ff40daa8771c1aa224ac46d5b224:
Richard Purdie (1):
methodpool: Improve method already seen error message

are available in the git repository at:

git://git.yoctoproject.org/poky-contrib seebs/tracking
http://git.yoctoproject.org/cgit.cgi/poky-contrib/log/?h=seebs/tracking

Peter Seebach (2):
data_smart.py: Provide (optional) logging of variable modifications data_smart.py: Track configuration file inclusions

 lib/bb/cooker.py         |    2 +
 lib/bb/data.py           |   65 +++++++++++++++++-----
 lib/bb/data_smart.py     |  140 +++++++++++++++++++++++++++++++++++++--------
 lib/bb/parse/__init__.py |    6 ++-
 lib/bb/parse/ast.py      |   65 ++++++++++++----------
 5 files changed, 209 insertions(+), 69 deletions(-)