Bundle of usability tweaks & bug fixes

- Moved period switcher to header
- Eliminated “point review complete” button. Rolled functionality into
next period button.
- Fixed bug that allowed empty incidents to be saved
- Style updates

@gregarious - Is there a reason you commented out the getForStudent
method in logEntryDataStore? It is causing an error to be thrown from
behaviorLog.js
Added orientation notice. Fixed empty counter bug. Enabled point costing while absent.
Automatically disable editing mode after a deletion
Updated absent labels
Merge branch 'bug-fixes'