Merge pull request #58 from mgage/release/2.7

Fix bug that left the TeX version of problemPostamble undefined.
Modified math4 to have a bigger box for problem bodies
Fix bug with problem width
Continuing to fix problem width bug
Merge pull request #60 from goehle/upgraded2.7

Problem Content Width Bug
Remove stray single quote after the problem-contents div
Merge branch 'release/2.7' of https://github.com/openwebwork/webwork2 into release/2.7