GA-6: initial game versioning
GA6 - added current version function -untested
GA-6: added new version to game
Merge branch 'versioning' of https://sat.inso.tuwien.ac.at/repositories/git/qse-ase-ws12-04 into versioning
GA-6: minor changes to game.current_version
GA-6: versioning games works; changed object_id to uuid string
GA-6: added Game.all_current_versions
GA-6: added redirect of show for old game versions to newest version
GA-6: removed old game versions from search_controller, ajax_controller, home view, games overview
GA-6: changed game db table names for versioning (with 'version_' prefix)
GA-6: fixed game rspec tests
GA-6: added reverting to Game
merged master into versioning, fixed mergeconflicts
Merge branch 'master' into versioning
GA-6: adapted versioning changes to master merge
GA-6: put versioning stuff in own class hierarchy
GA-6: added rake task (db:add_versioning) for adding versioning information to existing records (atm just games)
GA-6: fixed error when nil is passed to current object
GA-6: added db fields for versioning on Developers and Companies; added versioning rake task for developers and companies
resolved master merge conflicts