Update README.md
Update README.md
Initial demo page set up and modifications
Updated demo index page, replaced cc PNGs with SVG sprite
Added instructions beneath the credit card area
Add valid states at the end of the process
Replaced cc image SVG sprite with individual data URIs with PNG fallbacks
Fixed JS that was incorrectly applying the .card-image class to elements that aren't the card-image container
Edit .gitignore
Added ability to toggle card instruction on or off, CSS cleanup
Merge pull request #20 from bradfrost/master

Merging in changes from Brad Frost