Fixed grades issue for progress page graph.
TNL-1022
Merge pull request #647 from edx/waheed/tnl1022-fix-grades-issue-for-progress-page-graph

Fixed grades issue for progress page graph.
Fixed grades issue for progress page graph.
TNL-1022
Merge pull request #648 from edx/hotfix/2014-12-17

Fixed grades issue for progress page graph.
Update AUTHORS.
Keep distance between leaderboard and staff-info sections
Merge pull request #652 from edx/ammar/tnl62-fix

Keep distance between leaderboard and staff-info sections