Fixed the bug where late async submission caused an error in the is_submitted_late method of Submission because the submission_time field was not set. I think that if is_submitted_late is called on a Submission object that is not yet saved to the database, we can safely set the submission_time in that method.
Merge pull request #67 from Rubinous/async_late_submission_fix

Fixed the bug where late async submission caused an error in the is_subm...