Fixed some issues with the timedatepicker functionality. 

In particular time zones are no longer hard coded.

Since this is being pulled into master I would appreciate it if someone could give this some tested.  The only real changes are with the DateTime picker functionality on the Set Detail and the Homework Sets Editor 2 pages.  Make sure that the time zone after you change a date matches the time zone that was present before you changed the date.  (Also look for anything else out of the ordinary/buggy.) 

Thanks!