Delete folder/file fix

Fixes #29
Fix Section Regex

Fixed #33
Better use of AbstractUserStudent

Fixes #34
Better getNextExam()

Fixes #39
Fixes #40

getNextExam filters out completed exams and exams for other sections
all in the query. Instead of having to loop through the results and
having to do many more queries to see if it is completed.
Trip Bug fixes

Fixes #42
Fixes #44

Fixes problem where evaluations couldn't be given a grade of 20.
Fixes trip summaries rendering html instead of plaintext (no tags) in
the manage evaluation page.
Fixed bug where evaluation reviewers would see max points instead of
question for multiple choice questions.
Fixes #43
Fixed #50 (duplicate of 43)
Fixes #46
Front page layout

Fixes #48
Fixes #49

Instead of the forced column layout, I used the css property
column-count to create two columns. This makes the two columns
automatically try to be the same height. It is supported in all major
browsers, and fails gracefully when it's not supported.
Merge branch 'issues'