updated xpaths to match the current website design for livingsocial.com

Hello, I am new to Python and was working on the `scrape` tutorial, but noticed that the xpath references were incorrect. I changed the code, the documentation and the images to reflect the changes in the livingsocial.com website's design.

Oh, and I also, corrected some references to the **New York** city page, while the tutorial was covering the **San Francisco** city page.

*Disclaimer: I am fairly new to Github PR, so please go easy on me. :)*