Add EVM support

This PR needs https://github.com/zf-fr/zfr-oauth2-server/pull/15

I think this is the most flexible way, because it allows to retrieve the access token (which in turns give you access to things like owner, client...). As you also receive the response, you can modify it (like adding specific fields).

What do you think? If you liek it, I'll tag both libraries as 0.3.

ping @mac_nibblet