Added compojure.

This change required
  - the compojure libraries
  - a defroutes function with at least one route defined
  - Each defined route returns a ring handler. But the routes are being
  defined in the macro compojure-app, thus we need to use handler/site to
  pass the request to the routes in compojure-app, match the request against
  a route, then the handler gets returned and threaded by app.

Also updated project.clj
  - Added reference to main handler function
  - Added lein-ring plugin to enable lein to do ring stuff
  - Added profiles section with dev profile that uses ring-mock.