Cache the PyGithub Repository instance in the Cookie model

* Add basic functionality for repository forking
Don't complain about boostrapping in bakery.models
Add a test utility function to read replay_data
Fix some issues in the GitHub API
Started to mock Commands duing test
Don't complain about boostrapping in bakery.models (II) [travis] refs bbbcc32209
Add mocking for second command test involving the API
Merge remote-tracking branch 'origin/master' into feature/fork
ssss
Add tests for gh.get_repo_from_url
Merge remote-tracking branch 'origin/master' into feature/fork
Cleanup .travis.yml und tox.ini