Fixed bug where mathview buttons weren't associated to multiple essay boxes.
- Test by making a problem with two essay boxes and checking that the mathview buttons are placed to the side of each box.
Cleaned up the collapse button a bit.
Fixed the depreciation warnings that Perl >5.16 was generating.
Need to check defined on the reference, not the dereferenced array.
Merge branch 'release/2.9' of https://github.com/openwebwork/webwork2 into bugfixes
Merge branch 'bugfixes' of https://github.com/goehle/webwork2 into bugfixes
Fixed bug on Hmrk Sets Editor
REmoved "nowrap" from the classlist table.  It actually looks a little bit worse except for the fact that student names regularly overflowed their table cells.
Merge branch 'release/2.9' of https://github.com/openwebwork/webwork2 into bugfixes

Conflicts:
	lib/WeBWorK/ContentGenerator/Instructor/UserList2.pm
Small change.
- Fixed bottons spacing in problem set detail
- fixed the mark correct button functionality in the problem grader
- removed the hide hints column from the HmwK sets editor page.  Its not a traditional column (recently added), can still be changed by the problem set detail page, and I dont see why you need to know about it on that page.
- added PCC macro path (in libraries) to defaults.conf
-  Added some missing values to ProblemSetDetail.pm defaults.
-  Added htdocs/DATA to .gitignore
-  Fixed formatting issue with locations and confirm deletion
-  Changed it so that Showing Past Answers for a gateway set shows all of the answers for the visible questions.
Removed unnecessary tr: flats from .p files.
-  Changed userList2 so that filter now sorts on the visible labels for permission and status, rather than the codes stored in the db
-  Changed output_comments in Problem.pm to use the effective user and not the user.
-  Removed defunct sort options from HmwkSetsEditor
-  prettied up timer css on math4 gateways.
-- Made the ? .png into bootstrap icon in math4
Tweaked some labels on the Email and Scoring Tools page and added well formatting to form for Gateway sets on Student Progress.