Silex bridge and parameters' injection

Hi,

I wanted to use your bundle in Silex Micro Framework. The other one does not extends the different Symfony component and was not suited for my needs.

For the Silex compatibility, I removed the dependency with the Container and directly inject the needed parameters. This is in the first commit (1157978) You should now that I injected the request stack service so now the symfony min version should be 2.4. I think you should create a new release version if you accept my pull request because of it.

For the Silex implementation, I added a subnamespace Bridge where you can find the Silex Service Provider. This is in the second commit (0678287).

Every change has been tested on my environment : the symfony one on a symfony 2.4.3, the silex one on a silex 1.2.0.

I hope you will accept the request in order for me to use this bundle both in my SF project an in the silex ones.

Thanks in advance