Dependencies update

composer.lock file has been updated to use the lats version of
dependencies
Client Type support

This commit adds the client type support.
Now the server is able to find the client ID in the request using
multiple way.
There are two Finders in the standard library: Server Data and Body
Request.

A new library (oauth2-server-x509-client) has been created to allow the
server to find a client using a X509 certificate. See the repository for
more informations
Tests fixed
Composer now suggets to oauth2-server-x509-client
Token stores Client Object and not only client_id

The token sould store the client object and let the implementation
decide what is really kept in the storage.
Merge pull request #4 from Spomky-Labs/ClientInTokens

Token stores Client Object and not only client_id
Authorization and Access Token endpoints
Bugs fixed

Bugs suggested by Scrutinizer-CI fixed