Fixed test_system looking like a test to nosetests, also fixed a class in test_error_module.py that had one class inheriting from another
Added to author file
Rename system_test to get_test_system
Merge branch 'master' into blapenta/fix-test-coverage

Conflicts:
	AUTHORS
	common/lib/xmodule/xmodule/tests/test_annotatable_module.py
	common/lib/xmodule/xmodule/tests/test_capa_module.py
	common/lib/xmodule/xmodule/tests/test_combined_open_ended.py
	common/lib/xmodule/xmodule/tests/test_conditional.py
	common/lib/xmodule/xmodule/tests/test_html_module.py
	common/lib/xmodule/xmodule/tests/test_progress.py
	common/lib/xmodule/xmodule/tests/test_xml_module.py
	lms/djangoapps/courseware/tests/__init__.py
Fixes missing refactoring
Renames self.get_test_system to test_system, removes duplicate function.
Merge pull request #156 from edx/blapenta/fix-test-coverage

Fix test_system looking like a test to nosetest. Fix class inheritance causing double counting of coverage.