Update JSONProvider to handle a single element array

- Add serializeAsArray and arrayKeys to the JSONProvider in
  restContext.xml
Add a delete operation to ContentDao
Add a delete operation to ContentServer
Add a single page website using Spring Web MVC and AngularJS

- Add the mvc-website module containing a single
  Spring Web MVC @Controller that serves the index view
- Add the webapps/website module containing the Spring
  Web MVC config, index.css, index.jsp and index.js
Make webservices and website run on different ports

- Add cxf-rt-rs-security-cors to webservices
- Add corsFilter to webservices restContext.xml
- Add Access-Control-Allow headers to the website index
- Add OPTION request mapping and Access-Control-Allow headers
- Update content server URI to use localhost:8081 in index.js
- Add jetty plugin connectors assigning ports 8080 and 8081
  to website and webservices respectively
- Move jaxbProvider and jsonProvider under the contentServer
Update the instructions

- Explain how to run the webservices and website
  modules at once.