adding Canada support for Mercury
Add Gateway#scrub method to Gateway template, Gateway template tests Implement transcript scrubbing for Stripe gateway Implement transcript scrubbing for PayPal gateway

Closes #1481.
Merge pull request #1483 from Shopify/mercury_canada

Adding Canada support for Mercury
initial commit
add Stripe ICC (BER-TLV) data parsing, extract add_metadata method
add clarification for the icc_data accessor on CreditCard
add emv_authorization attribute to Response, corresponding to the EMV-specific authorization response targeted back to the EMV chip
include EMV authorization response for Stripe EMV transactions
customer, flags, and fees data should not be included for EMV transactions, update to grizzly_ber-0.0.2
Splitting off more ICC data elements for the receipt
omit capture flag for EMV authorizations
include card[icc_data] field on capture to forward EMV TC message