lml/ost#341: Fix prev/next navigation query and some UI issues.

- The peers scope was incorrectly using an assignment instead of
  a query.  Used a method instead of scope.
- Corrected typo "availble"
- Changed navigation items from "Go to x" to "x"
- Removed the Exercise link from feedback nav.
- Reordered class and assignment in AE nav as in other pages.
- "Your free responses" title cased.