Force use of dev-develop as v0.9 doesn't work

Hey,

I want to work on getting a more fully implemented Symfony 2 version of your PHP library written. First thing I noticed is that the dev-develop branch has to be used in Symfony because the class was previously named OAuth2_Server instead of just Server which the dependency injection doesn't like.

Don't know how familiar you are with Symfony 2, I wouldn't call myself an expert, but maybe if I do some stuff you can check it over and see if it's any good.