Added PreparedTestRequest class.

* What is passed to the test harness will be whatever
  PreparedTestRequest.to_dict() returns.
Merge branch 'v0.2dev' of github:brownhead/galah into v0.2dev
Implemented basic actions.

* Submissions may either be marked as public or final and Galah will
  provide the test harness with the appropriate actions as specified
  in the harness's configuration file.