POST multipart forms fail to authenticate

[alanhartless]

We are writing files over an API endpoint in an app that leverages https://github.com/FriendsOfSymfony/FOSOAuthServerBundle where multipart forms are used by curl. But it seems that multipart forms are not supported by https://github.com/FriendsOfSymfony/oauth2-php/blob/master/lib/OAuth2.php#L645.

As a workaround, we have to make a special case of appending the access token as a query parameter instead.

Is this on purpose or simply an oversight?