Add evolution part to buildout.cfg

Provides an "evolve" tool which looks for out-of-date packages
Upgrade packages

Including Django to >1.6,<1.7
Fix imports of url functions
Fix URL tag usage
Remove superfluous "load url from future" tags
Update deprecated usage of django-guardian "assign"
Merge branch 'feature/package-upgrade' into develop

Upgrade packages, including to Django >1.6,<1.7