* Rework job processing in light of Rails 5's Reloader, see #3221
* Ignore built gems
* Documentation, testing
* Add fallback for 'retry' value server-side, fixes#3234
* Fix job hash reporting in stats
* cleanup
* Add job for AJ testing
* Push jobs with invalid JSON immediately to Dead set, fixes#3296
* Break retry logic into global and local parts, fixes#3306
* fix heisentest