Adding optional monkey patch for Mechanize

As advised here:
http://scottwb.com/blog/2013/11/09/defeating-the-infamous-mechanize-too-many-connection-resets-bug/

This is issue 123 on the Mechanize gem and hasn't been closed in
over two years. This allows the gem author/maintainer to require
the monkey patch specifically. Only seems to be an issue with long
running scrapers so far.