Clean up test suite.

Combine two contexts for the same thing.
Clean up submission details.

* Remove divs around <dt><dd> elements to be standards compliant.
* Style the public button to make it look like other buttons.
Hide button to update other user's submissions.
Include a link to view submissions.

Only display link if used is logged in and the lesson is a
challenge.
Include link back to lesson path from submissions.
Use breadcrumbs for navigation.

Provides a more consistent interface to move between lessons
and submissions.
Merge pull request #79 from atsheehan/update_submissions

Clean up views.