Summary: Ref T4324. The server code is probably going to get a fair amount more complicated, so allow it to load Javelin classes in a mostly-reasonable way. This integration has a few warts, but should be good enough to let us manage complexity through the next iteration of the server. (Mostly I just want the concicse Javelin mechanism for defining new classes.) Version bump is just so I can figure stuff out if this creates any issues for users based on which version of things they're running. Test Plan: Started server, posted some messages through it. Reviewers: btrahan Reviewed By: btrahan CC: aran Maniphest Tasks: T4324 Differential Revision: https://secure.phabricator.com/D8253