Prevent admins from adding blank rdbtn opts to e.t.

- Prevent admins from adding blank radio button options on edit
  evaluation template page
Fix bug that prevented "mandatory" from changing

- Fix bug that prevented "mandatory" from changing if order of questions
  switched (on the edit evaluation template page)
Implement Parsley.js for client-side validations

- Use Parsley to ensure that admins cannot submit edit evaluation
  template forms with blank fields