global: pep8 and license

Signed-off-by: Yoan Blanc <yoan.blanc@cern.ch>
global: refactoring

* Fixing the problem unhandled during the "pending" states addition.

Signed-off-by: Yoan Blanc <yoan.blanc@cern.ch>
global: version.py

* Adding back version.py file.
  http://python-packaging-user-guide.readthedocs.org/en/latest/tutorial.html

Signed-off-by: Yoan Blanc <yoan.blanc@cern.ch>
docs: the docs

Signed-off-by: Yoan Blanc <yoan.blanc@cern.ch>