Make subscription payment available through Subscription#payment
Merge pull request #26 from jacegu/payment-in-subscriptions

Make subscription payment available through Subscription#payment
Add the #update_attributes method to Update. This takes an id and a Hash of attributes to update.
Add origin_amount as accessible attribute to transaction
Add info on refunds to the readme
Merge pull request #29 from theodorton/refund-readme

Add info on refunds to the readme
Merge pull request #28 from theodorton/origin-amount

Add origin_amount as accessible attribute to transaction
Merge pull request #27 from Nerian/master

Add a class method to update a subscription
We use double quotes
Extracts resquests into their own class

There is no need for the paymill module to know about the internals of a
request, that can be hidden away in its own class
Moves https setup into a private method
Request related classes now have a single responsibility
Applying Sandi Metz rules
Payments in sync with API
Adds Payments to the README
Removes some data dependencies
Removes the data dependency on response
Removes more data dependencies
Refactors tests
Removes test file