Show selected tab on report reload
Merge branch 'master' of https://github.com/Stanford-Online/class2go into giulio-reports-reload-2134
Work for #2129 - Drill down to assessment summary report from quizzes
summary in-line report.
rewrote if logic to be positive
Implement decorator to force draft mode switch

* Implement courses.actions.always_switch_mode decorator to force a
  function to always be run in draft mode.
  (addresses #330)
* Minor bugfix to File Upload dialog and test of decorator on it.
Deployment and testing of always_switch_mode

* ```@always_switch_mode wrapper``` installed and tested in following places:
  * File Upload/Edit/Delete
  * Exam Edit/Save/Delete
  * Video Upload/Edit/Save/Delete
  * Content Section Rename/Save/Delete/Move
  * Static page Add/Save/Delete/Move
  * Announcement Create/Edit/Delete

* Decorator updated to only switch mode if mode switch is necessary
* Cleanup of unused imports in a variety of places
* courses/email_members audited but mode switching didn't seem necessary

(closes #330)
Removing DEBUG output from @always_switch_mode
keeping tab selected after generating reports
Merge pull request #2251 from Stanford-Online/dca_new_working2

Work for #2129 - Drill down to assessment summary report from quizzes summary in-line report.
Merge pull request #2222 from Stanford-Online/giulio-reports-reload-2134

Show selected tab on report reload
Make the exam label width not 100% -- student issues
disable start button after click to avoid race condition
Merge pull request #2259 from Stanford-Online/jbau-exam-label-css

Jbau exam label css
collect_data modification in exams/views

return 403 on submissions whose attempt number is > than the max
allowed by exam.  previously this check was only on rendering the
exam page.
incorporate exam submission deadline in timed-exam endtime
add "student" option to regrader
Handle missing examrecordscore
regrade: import ExamRecordScore model
regrade: error check for ExamRecord.attempt_number=0
Merge pull request #2263 from Stanford-Online/sef-regrade-options

Regrade improvements: student ID option, robustness (to Master)