* updated coinbase nuget url.
* Removing TotalNative for existing Price object
* Removing RefundTransaciton for existing Transaction model
* Refactored API with better usage semantics RefundOptions
* Added support for "mispayment" refunds
* Refactoring with existing domain model
* Merging #5 to master with some refinements.
* Adding errors field in Refund Order
* Fixing Integration Test
* Updated README
* Refund integration test fixed.
* Fixing some README typos.
* Prepping v0.3.8 version
fixes complication error and null reference exception
updated build file