Worldpay: Improve address defaulting

We've seen that Worldpay can, without warning, turn on the requirement
for address1 and city.  Previously, we were defaulting things like
postal_code and state.  Now we default more of the address fields if
they're not specified.

In theory, this should help some customers, it shouldn't hurt any
existing customers, and it should help customers down the road if
Worldpay changes the address requirements on an account.

Closes #1310.
Update net_registry URL
Merge pull request #1312 from Shopify/net_registry_url_update

Update Netregistry URL
Authorize.Net: Add maestro as supported card type

Maestro is supported as a card type by some merchant accounts that
Authorize.Net backs up to. Unfortunately the Authorize.Net sandbox does
not support Maestro, so a remote test was not possible.

Closes #1304.
Worldpay: Improve address defaults

Previously, we defaulted parts of the address that were unspecified.
Now we also default the parts that are explicitly set to a blank value.

Closes #1311.
Braintree Blue: Pass name when tokenizing

Closes #1306.
Braintree always charges default card if you pass customer_id.  Change to payment_method_token in order to allow charging any card. https://developers.braintreepayments.com/ios+ruby/sdk/server/transaction-processing/create-from-vault#customer-id
Braintree: Add regression to ensure payment_method_token is used in favor of customer_id.
Make payment_method_token an option.
Add remote test for payment_method_token.