Only run code coverage on Django 1.5

At the moment, it's not clear to me how coveralls handles build
matrixes for its master coverage report. It looks nondeterministic,
probably based on whichever finishes first.
Factor out setup tool
More tests
Merge pull request #28 from steventlamb/topic/increase_test_coverage

Topic/increase test coverage
Merge pull request #27 from steventlamb/topic/run_coverage_on_django_1_5_only

Only run code coverage on Django 1.5