- Changed the maven web container plugin from Jetty to Tomcat so that we have access to the Servlet 3 interface.
 - Added exclusions in the Spring Data dependency to fix some class clashes.
 - Updated the web.xml so that it uses the new web-app_3_0 schema.
 - Configure the DispatcherServlet to have async request support.
Updated all the CRUD methods to be asynchronous.