Add basic RemoteRepositoryTracker test
Test detection of BranchCreatedFromAKnownCommit
Test detection of BranchResetToAKnownCommit
Test detection of BranchDeleted
Test detection of BranchCreated
Test detection of BranchUpdated
Test detection of BranchForceUpdated
Minor refactoring
Fix detection of creation of a new root branch
Introduce DummyEvent
Rename Event to RepositoryEvent