Remove dead css, refactor survey/questionssummary

Started off just removing no longer used css. Ended up refactoring how
questions are edited in surveys.

Since questions can now be viewed in the regular survey view, I've
removed the dual mode is_editable option for questionssummary. Questions
are now always assumed to be editable. The controller will check for
submissions in the survey, and if there are any, will deny access to
questionssummary. questionssummary really should be renamed to
editQuestions.