Tweak approval state and simplify continue button

Changed approval UI to respond differently for the user and coach. The states are the same, however, when a user submits a task or assignment, it shows as "done" whether it's actually been reviewed or not. The coach now sees wording that says "review" instead of "approve" as well.

Also removed submit button and have continue button submit form with or without section data so it is consistent. Also removed need for ajax on form submittal for now. Now a single continue/finish button replaces the two previous buttons.