Make sure the overridden find_runs is tested.

This is one of the overridden methods in this application's RunsController.
Move the RunsController tests into the correct namespace.

RunsController is overridden from Taverna Player so the tests should be in that
namespace. It doesn't make much difference in practise but good for consistency.
Add comments to (and tidy up) the routes file.

It wasn't obvious why certain lines are in there.