User agent update

Hi there,  

Just a small update; changing the user-agent in the request to reflect what is in the 'Best Practices" page here : http://mygengo.com/api/developer-docs/best-practices/

This is to help us at myGengo keep track of the submits that are made via the API from our libraries and plugins. 

Please pull this change, and thanks in advance !

Lloyd

Engineer at myGengo