Remove unneeded require.
Stripe: Include swipe_data parameter if provided.
Use track_data instead of swipe_data on the AM side.
Include a track_data attribute on the credit card class.
Swipe_data and traditional card information are mutually exclusive.
Add unit & remote tests for stripe.
Merge pull request #730 from Shopify/stripe-card-present

Stripe: Include swipe_data if provided.