Create db migration to change test_result model:
  - remove completion_status, input_description, actual_output, expected_output fields
  - add marks_available, description, feedback fields
Change test_result validation and documentation to
match DB model migration
Change parsing to match test_result model changes
Make interface changes to match test_result model changes
Merge pull request #33 from JeremyMerkur/ATE-issue-22

Implementation for issue-22: XML Test Results Protocol