Merge pull request #65 from gotoalberto/okpaymock

Introduce first OkPaymock test
Refactor okpaymock module

 * Remove useless logging
 * Extract payment processor details to a model package
 * Use ActorPath instead of unsafe strings
 * Introduce FaultOr[T] type alias
 * Several renames and style fixes
Merge pull request #66 from sortega/okpaymock

Add ‘create account’ ‘retrieve balance’ and ‘destroy account’ on OkPaymock
Implement of SendPayment() on okpay mock
Merge pull request #68 from sortega/task/70_send_payment

Implement of SendPayment() on okpay mock