1077423 overhaul generic

TOTAL GENERIC FORM (DEV VERSION) OVERHAUL!

This is a big change. To see it in your browser:

1. do `./manage.py runserver`
2. visit `/feedback/?feedbackdev=1`

To review:

1. check out the CSS--it's a completely new file, so don't bother looking at the diff. does it look ok? am i doing dumb css things?
2. check out the js--i reused a bunch of stuff, so i'm feeling pretty ok with this.
3. check out the html template--does it look ok?
4. run the tests.
5. run the smoketests if you can.
nit: so you usually want to try and avoid `!important`. it's better to increase the selector specificity to make sure the property gets overridden. but in some cases you do need to use to it (like if you want this to apply to all `.invalid`'s and not be overridden by more specific selector rules). if this happens to be one of those cases feel free to ignore this.