addressed issue https://github.com/globaleaks/GlobaLeaks/issues/485

Conflicts:

	globaleaks/db/__init__.py
fix against issue https://github.com/globaleaks/GlobaLeaks/issues/415
added migration script for issue/415
fixed issue https://github.com/globaleaks/GlobaLeaks/issues/467
addressed issue https://github.com/globaleaks/GlobaLeaks/issues/482
issue/415 complexity reductions (thanks to vecna suggestions)
Fix bug in importing of models
addressed issue https://github.com/globaleaks/GlobaLeaks/issues/485
aligned migration script to last commit changes
fixed updating script against 4 populated db: 0,1,2,3->4
addressed issue https://github.com/globaleaks/GlobaLeaks/issues/296
Merge branch 'issue/415' into devel

Conflicts:
	globaleaks/tests/test_gpg.py
changed default of expiration key checks
Merge branch 'issue/296' into devel
Merge branch 'issue/485' into devel