Feature Request: add display options to client_params

[feddgs]

Hi!

It would be nice if the gem can support the :display parameter in the client params method, now i have my omniauth-foursquare gem patched in this way:

def client_params
{:client_id => options[:client_id], :redirect_uri => callback_url ,:response_type => "code", :display => options[:display]}
end

The :display is set in the omniauth initializer as :display => 'webpopup' and work great for me.

Thanks for the gem!