Fixed a bug in the handling of multiple charges to the same customer
New IATS Gateway
MerchantWarrior: Fix handling of amounts

The gateways can take in a Money or an integer in cents.  Then under the
covers it sends the amount in the right format to the actual gateway.

The Merchant Warrior gateway class was taking in a string dollar amount
rather than behaving like the other gateways.
Merchant Warrior: Send the CVV to the gateway

Closes #795.
Eway: Update supported countries

Eway is now also available in the UK and New Zealand.
Fix status messages for PayU.
Merge pull request #793 from Shopify/add_iats_gateway

New IATS Gateway
Merge pull request #799 from Shopify/fix-payu-status-types

Fix status messages for PayU.
SecureNet: Allow production transactions

The TEST parameter was always being sent as true!  Now we only pass that
parameter at the right time.

Closes #805.
Stripe: Allow a card_not_present_fee to be specified.
Refactoring instance variable to a method.
Stripe: Fix a broken remote test due to an error message change.
Merge pull request #807 from Shopify/stripe-card-not-present-fees

Stripe: Allow a card_not_present_fee to be specified.
Bump for release v1.37.0
Revert "Stripe: Allow a card_not_present_fee to be specified."
gemspec: Dont force nokogiri lesser than 1.6.0

Nokogiri drop support for Ruby 1.8 with nokogiri 1.6.0.
It fix a lot of bugs with libxml2 and others.

* https://github.com/sparklemotion/nokogiri/commit/7c5f3f6c444b73192abbcc19ef9e3c987cdf7ab0

And force a user to downgrade his nokogiri version is not very friendly to
a project that want to be up-to-date.

ref #765
Firstdata E4: Include missing address information for AVS and CVV results.
Allow changing the primary response of a MultiResponse to the first one run.
Stripe: Make the actual refund response primary rather than the fee refund.
Merge pull request #813 from spk/nokogiri_bump

gemspec: Dont force nokogiri lesser than 1.6.0