Project editor

This is a *work in progress* project description editor replacement. Don't merge until all todos are done :)

- [ ] find a decent markdown parser/editor combination (ended up being marked/pagedown)
- [ ] implement it in solvers. Made a standalone package for this: https://github.com/Blahah/meteor-pagedown-bootstrap, then built a little wrapper to allow toggling editor and preview states.
- [ ] fix css weirdness (editor overflow on resize, bullet points next to project list)
- [ ] test marked syntax is all working (including tables, centering, etc.)
- [ ] catch edge case where tables display funky (need to jquery-patch pretty table classes after render)
- [ ] test on other browsers (so far just Chrome OSX)