Google Scholar search engine by Christian Ponte

Adds a search engine for Google Scholar (<a href="https://prod.outgoing.prod.webservices.mozgcp.net/v1/48d81c56e9cd5e25be3a4a4e11ccde88735294aaf34179bea41368573afe60dc/http%3A//scholar.google.com" rel="nofollow">scholar.google.com</a>).