Updated:

- Don't need to exlicity add 'jettywrapper' to Gemfile b/c added by hydra:head generator (called by sufia generator)
- Don't need to remove public/index.html (Rails 4 presumably)
- Run `rake jetty:clean` instead of hydra:jetty generator -- does the same thing
- Added note that fits can be installed with homebrew (and may require adding a symlink)