Fixed Overwrite grader and creating a new mark, immediately saving it wouldn't work and publish is now implemented

* Now shows former hidden marks in create/edit gradeable

* missed something

* missed something

* fixed that when you add a new mark and save it, it won't save

* fixed overwrite grader as well

* added publish

* wip

* Marks should no longer clobber each other

* readded delete components

* recommented delete questions. still broken. oops

* Publish now works

* wip

* wip

* it works? may test later

* add allow_late_submission boolean

* add time zone to gcd_grade_time timestamp

* add update_database.py script (written by Matt)