Fixed mathview so that it doesn't look janky on small screens.
Cleaned up MathView a little bit. The big changes are

1) It now supports latex editing.  Just add the class latexentryfield to a text area and it will make a button for a mathview latex edior
2) Added this mathview latex editor functionality to PGProblemEditor2/3.  It can be turned on and off by a config variable (which is not in the Course Configuration area)
Added the ability for mathview to work with essay answers.
Merge branch 'release/2.9' of https://github.com/openwebwork/webwork2 into mathviewups
Small tweak to make formatting on editor page look nicer
Fixed cursor position for intervals.
added comments
Merge pull request #335 from goehle/mathviewups

Mathview Upgrades -- The cursor is inserted in the correct position when inserting interval notation.