Exposed a bunch of IInvoice and IPayment extension methods to allow front end designers to more easily integrate Plugin payment providers.
Updated Umbraco dependencies to 7.1.1
Replaced hard referenced Merchello dependencies with Merchello.Core NuGet reference in AuthorizeNet provider. Patched AuthorizeNet integration tests.
Merge pull request #531 from rustyswayne/1.0.1

Bunch of stuff relating to payment providers