Small changes for stable release 3

This branch contains several small fixes in accordance with the tickets I assigned myself for this release.  They address the following tickets:
- #488 (Survey review_single is broken)
- #385 (Send schedules without room numbers from comm panel)
- #221 (Class sorting on Dashboard)
- #414 (Confirm Pre-registration button not appear if bit isn't set)
- #419 (School/k12school field on student profile)
- #284 (SplashInfo stats on Ajax admin vitals)
- #302 (Template override cache doesn't handle inheritance)
- #110 (Teacher availability not always saved properly)
- #476 (Class changes grid should show closed classes differently)

If someone could test this and review the code that would be great.