Found a broken symlink.

I have no idea whether this file actually gets used.
Close a bunch of div tags.

Found by scanning with tidyhtml and then inspecting manually
(since we have to take Django template conditionals into account).

Hand-tested by eyeballing against MIT's layout as of 2010 or so,
which is sensitive to both insufficient </div>s and excessive </div>s
(the copyright message at the bottom gets displaced).
Fix a bunch more tag closings and tag names.

Of particular note is the change to esp/templates/users/userview.html
which allows the teacher's major to display where it's supposed to in
the table.

The rest usually did not have visible effects.

Amusing patterns spotted:
* Tags which closed themselves and weren't supposed to (e.g. "<td/>")
* Tags which were missing their ">"
Merge pull request #678 from pteromys/tidy

HTML housekeeping