Daos should have a consistent contract, false on error? Move all logic to controllers

[jakethedev]

There isn't a consistent approach, and sometimes we're returning string results from the dao to the user via controller. This is nasty, and not in the hot way, so it needs to be fixed, documented, and followed.

Additional thoughts: look up a good SQL / Mongo driver api, see if we can think ahead and have controller logic already in a healthy place for that transition

Blocks #21 (migrating to a database)