Add unused revert_last_merge, use StandardError for exceptions
Restructure tick to allow a merge to be reverted when build fails
Use StandardError (instead of Exception) for all other exceptions
Check scratch dir is a git repo before attempting revert
Add SCRATCH_DIR config variable
Move revert_last_merge from Lollibot to Repository
Extract execute_merge from execute_next_merge
Add merge request start endpoint.  Gives merge request ID to IRC bot
post /build/started no longer takes pr_id.  Merge request found by being only one in progress
post /build/succeeded no longer takes an ID.  Associates with merge request in progress.
Add REST and IRC (!status) functionality to see if a merge request is in progress
No longer checking against build ID when polling CI.
Add .travis.yml