Unify in a single file all tests checking that access to actions is properly restricted.
Remove a lingering reference to Artist.active.
Add tests ensuring that GET request-based actions follow expected access restrictions.
Correct an oversight in file naming that caused route specs not to run by default.
Fix errors in the bounty routes tests.
Fix errors in the session route specs.
Add tests that unused actions by some controllers are unroutable.
Don't provide routes for controller actions that have no logic.
Fix up style offenses in new routing tests.
Controllers now attempt to send the user to the previous page on error.

As a user-friendly feature, our controllers should do their best to send
the user back to the page they were at before an error occurred instead
of dumping them back on the site's root page every time. Because
redirecting the user back requires the HTTP_REFERER header, we still
send the user back to the root page if they don't have that header set.
Remove a FIXME comment.

The old FIXME requests the user be redirected to their dashboard on
login. In hindsight, it's better to keep the existing behavior of
sending them to the site's root page because that's intended to the main
page for the site.