R1:c93fc91e96aa

Update Javelin; improve package definitions

Summary:
- Update Javelin to HEAD -- this doesn't pick up anything in particular, but
lets us smoke test some stuff like {D1217}.
- Do a little more packaging since we've picked up a handful of 10-line
behaviors and such for various UI tweaks.

Test Plan:
- Generally, this should be very low-risk.
- Browed Maniphest, Differential, Diffusion and tried to hit all the JS
interactions.
- Looked over the Javelin changes we're pulling in to see if I forgot…