Improve moving requests between divisions

Remove leftover lines from Flask-Principal, add tests.
Use a custom jsonify wrapper for including flashed messages
Adding/Removing an entity from a division now shows the correct status

Also rewrote a portion of the javascript for the division details page.
Start organizing JS into a module, starting with the request stuff
Handle message flashing in an AJAX event

Keeps it from every request having to provide a 'complete' callback.
Clear the hidden 'id_' field when adding entities to a division
Set the modifier timestamp at instantiation

Before, it was using a single datetime instance.
Move division detail JS to the new module
Rename custom handlebars helpers to a slightly better name
Merge custom-typeahead.js into ui-division.js

It was weird to have them split in the first place. Also fixed #26 while I was in there.
Pull custom-pourover.js apart into multiple files

Attempting to make it more manageable, and I think I got partway there. I'm still considering ripping PourOver out entirely.
Merge branch 'javascript-reorganize'

* javascript-reorganize:
  Pull custom-pourover.js apart into multiple files
  Merge custom-typeahead.js into ui-division.js
  Rename custom handlebars helpers to a slightly better name
  Move division detail JS to the new module
  Clear the hidden 'id_' field when adding entities to a division
  Handle message flashing in an AJAX event
  Start organizing JS into a module, starting with the request stuff
Release v0.9.0