Start application process

Moved enrollments controller to users controller and will use enrollments for new applications. Renamed a bunch of stuff involving enrollments to be "user" as needed. Setup base form for enrollments with prototype of autocomplete per Ehud. Cleaned up related javascripts and consolidated. Added enrollment model and associations.
These were placeholders from the autocomplete example just so I could prototype the autocomplete Ehud wanted on the application form. I didn't really have a list of majors that we wanted in there as a starting point. Should we get a list of them now and put them in, or just deal with that when we build out the actual form?