API Refactored and set up DI properly in it, Upgraded to Symfony 2.3

I've refactored the hackathon REST API bundle and setup DI properly in it.

At the moment we have to still do:

- create previous/next links
- build more controllers / settings for more API support
- In the future create post/put/delete actions, support is already there

Since i've upgraded the project to Symfony 2.3, its as easy as composer install again.