Prepared server application for Heroku deployment.

 - Added a package.json file for NPM.
 - Added a Procfile so Heroku knows how to start the app.
Decoupled representation and server modules.

 - Created a new DomainServer object to wrap the server functionality
   in.
 - Moved crawler and domain manager elements of server.js to new app.js.
 - Fixed some port issues with Heroku.
 - Fixed a possible Domain load bug when domain url is invalid (for
   instance, in a blank Domain object intended to be loaded with fromJSON()
   rather than the constructor).