notes
1. Synopsis from stackoverflow.com
http://stackoverflow.com/questions/8482543/what-are-some-examples-of-using-nokogiri
2. Getting Started with Nokogiri
https://www.engineyard.com/blog/2010/getting-started-with-nokogiri/
3. Tutorial book
http://ruby.bastardsbook.com/chapters/html-parsing/
4. XML search examples
http://ozmox.com/blog/2009/11/15/nokogiri—cut-with-precision/