Refactor messy, logic-heavy views

[mnquintana]

Whenever I get the chance, I'm going to go through all our views and refactor as much logic as possible into helper methods, to keep our views clean and more easily maintainable going forward.

[shippy]

To what extent should the views be refactored? For instance, is the duplication in #226 tolerable, or would we want that abstracted?

[shippy]

For posterity: yesterday, #660 refactored UsersController#new.

[squidgetx]

I think we're generally good here: we can continue to refactor as we go along but I'd like to move forward to 4.0.0. Thoughts?

[orenyk]

I think this is reasonable, we can add specific issues as they come up.