Mering my branch (pv) in to master.

### Notes
User registration now fully links enrolled, subscribed, and program to user document in the Users collection. 
Still need to enable and configure authentication permissions within ui-router, create user service (this returns an user `_id`) and update all queries so it returns data for the signed in user. 

`npm install` is required, as I've added some new modules. 

### Using Q
View the post request for /user and check out the [Q site](https://github.com/kriskowal/q)