__Functional test

This PR aims to:
- add some bundle to perform functional test.
- remove the AcmeDemoBundle
- created unit test
- the service PageHandler which instead of the controller, contains the logic to retrieve the information.


Notes:
- while installing the bundles if you get the following error `Fatal error: Allowed memory size of 536870912 bytes exhausted (tried to allocate 79 bytes) in phar:` you can run the following `php -dmemory_limit=1G composer.phar update`
- to run the test `bin/phpunit -c app`

References:
- http://welcometothebundle.com/symfony2-rest-api-the-best-2013-way/
- http://williamdurand.fr/2012/08/02/rest-apis-with-symfony2-the-right-way/