Added link to toggle closed rounds, made them hidden by default
Late submissions were not allowed at all by the BaseExercise.is_submission_allowed.
Merge pull request #86 from Rubinous/master

Fixed the bug where late submissions weren't allowed at all
Merge pull request #79 from vkaravir/toggleClosedRounds

Added link to toggle closed rounds, made them hidden by default
Merge branch 'master' into apps