Show authorized roles in key icon tooltip

This modifies the tooltip of the key icon of every method to show the required roles, if any available. To set authenticated roles, use the `authenticationRoles` field of the `ApiDoc` annotation or use the JMSSecurityExtraBundle's `Secure` annotation which is read automatically.

Test cases provided, however some unit tests fail as before forking.

![tooltip](https://f.cloud.github.com/assets/1026940/695236/57b0fb52-dcca-11e2-80f3-740b79a19bfd.png)