UI for solutions

[kjdav]

One of the instructors suggested it'd be useful to be able to quickly preview solutions in the same way that you can preview questions: "it's a real pain to get the typesetting correct when you have to keep adding and deleting solutions (with text saved outside OST so you don't lose it)."

From this exchange, it also became clear that he didn't realize he could edit his own solutions, so perhaps we should make the Edit icon more prominent somehow. Maybe text instead of the icon? Or add the "Edit this Solution" link to the lefthand menu?