Fulfilled some requests

Fixed bug where register account link was still public.
Fixed bug where hitting return on exam question search would submit
form.
Changed default points per question to 2.
Added notifications checkbox/start date in trip global

Also made student list show up to trip leaders.
Trip fixes

Added optional notification of trip drops/adds
Made full trips appear grayed out
Fixed bug where you had to sign in twice to get to trip leader page.
Bug fixes
Download list of students signed up for trips

Student with no trips at bottom
Exam timing fix

Fixed bug where no one could grade after the test end time had passed.
Also fixed bug with displaying practice exams for review.
Rewrote Exam controller
Initial run bug fixes.
Made review work

Now it shows comments!
Move back to public bundle.
Made exam uncacheable, multi-grading bug fix

Fixed bug where grader could see and edit all previous graders grades.
Bug fixes

Fixed bug where people were only allowed to grade/be assigned once.
Fixed bug where check would automatically increment your status when it
paired you with someone, meaning you could skip the wait screen by
refreshing.
Fixed bug where you could be assigned several times in a row.
Made some style changes.

Fixed unrelated bug in trip bundle where teacher notification subject
line always said a student dropped a trip even if they joined.
Better timestamps!
Review untaken tests

Added ability to review tests you didn't take.
Merge pull request #100 from dmhurley/exam-fixing

Exam fixing
Whoops.

Forgot to commit before merging...
Merge branch 'exam-fixing'
Fixed some javascript
Updated exam download
Toggle forced comments

Added a checkbox to make grader comments switch between optional and
mandatory.