status_tests.py: Tests Summary.py's assignment of statues

This code tests the way Summary.py assigns statuses to tests.
Specifically it tests regressions, fixes, changes, and problems,
assuring that only the correct permutations of these tests are added to
the list.

It uses python's builtin unittest framework, and a magical decorator to
limit code duplication.

This already reveals 8 problems in the current implementation
piglit-framework-tests.py: Adds a utility for running piglit unit tests

This program gives the option to run the tests. These tests are meant to
test internal features of the piglit framework. Currently there are only
tests for the summary module's handling of regressions, fixes, changes,
and problems.