252 superfish

This pull request, created on top of Thomas' #234, restores the look of Shifts. This is achieved by re-integrating some of the old CSS stylesheets back into rails-3.2, and putting the newest superfish.js and hoverIntent.js into the assets folder. The old superfish-rails gem is not updated for a year and I have removed it from Gemfile.
There is one remaining front-end issue: The menu item on the navigation bar that contains sub-menus are missing a downward arrow
This pull request also moves all the JavaScripts under vendor/ to vendor/assets/javascripts/.
We are thinking about getting rid of superfish altogether and use bootstrap instead for the menus. But this is a working version of the navigation bar. 

[See the compare](https://github.com/YaleSTC/shifts/compare/asset_pipline_stylesheets...252_superfish?w=1)