Fixed various forms to be bootstrap3-ified

In passing, also improved the design of the "edit profile" page (https://www.pivotaltracker.com/story/show/53680865)

I think this concludes the b3ification, and we're just about ready for people to push it up and see.

@sabreuse, I'd appreciate your opinion on this!
Typo: "chang" should be "change".