Implement framework for testing API...

... if you can call 1 new class a framework. Includes a few test cases to exercise/drive it. These examples include a histories API test (a typical API test) and a general test of the API framework itself (mostly just the run_as functionality).

This includes changes to interactor.py to make it more useful outside the context of tool/workflow testing as well as a tweak to test Galaxy that gets started to allow testing of the run_as feature.
Add API functional tests for Kyle's page API methods.
Remove non-api functional tests. DO NOT COMMIT TO GALAXY-CENTRAL.