MERCURY-SPRING-0004: RESTifying

- Previous changes:
· Change the pom's packaging to WAR.
· Renamed ApplicationConfiguration to MongoDbRepositoryConfiguration.

- Bootstrap Spring MVC: 
· spring-webmvc dependency (and a provided javax.servlet-api too)
· spring-data-rest-webmvc dependency (seriously, -webmvc? :@)
· RestExporterWebInitializer
- Starting the REST application
· RestExporterWebInitializer

- Minor changes:
Updating documents (txt)