[feature] Configure phpunit & add RequestListenerTest

It should be easy then to configure travis-ci to build this bundle.
A ```.travis.yml``` file like that
```
language: php

php:
    - 5.3
    - 5.4
    - 5.5
    - 5.6
    - hhvm

matrix:
    allow_failures:
        - php: hhvm

before_script:
  - composer install --prefer-source --no-interaction

script:
  - phpunit --coverage-clover=coverage.clover
  - wget https://scrutinizer-ci.com/ocular.phar
  - php ocular.phar code-coverage:upload --format=php-clover coverage.clover

notifications:
    email: false
```