license.bbclass parsing changes rebased

Using python abstract syntax trees as a parser and an ast visitor class, I've begun the first steps to being able to put some sanity to license selection.

One note. License modifiers have traditionally been limited to the "or greater" modifier "+". I've added another modifier "with exceptions" for licenses that have no generic ie common-licenses/GPL-2,0-with-GCC-exception

The modifiers are ignored for now, but I'll be looking at the logic for them next.

The following changes since commit 62e3f0ff7b27d8beb21b4b226051c3db654ea4e4:

License Field Cleanup: Non-standard field names (2011-05-27 18:27:22 +0100)

are available in the git repository at:
git://git.pokylinux.org/poky-contrib eflanagan/common-licenses
http://git.pokylinux.org/cgit.cgi/poky-contrib/log/?h=eflanagan/common-licenses

Beth Flanagan (1):
license.bbclass: Sane Parsing of licenses

 meta/classes/license.bbclass |  155 +++++++++++++++++++++++++++++++----------
 1 files changed, 117 insertions(+), 38 deletions(-)