Use WebPageTest and do diffs on the image results for Regression Testing purposes

just do an npm install and ask me about a config.js file ; ]

run like node index.js '6/28' '6/29' from the project root.

@TODO:

• figure out the best way to input dates
• do we store old screenshots? How long / is that even really useful?
• where should this live? CRON job?