Implemented VTDirect initialization
Added validation logic to request.Address subentity
Refactored request entity validation logic into a base class
Implemented request.TransactionDetails entity and tests
Implemented the remainder of the request entities
Added error codes.  veritrans.request.* to use a single common mixin that triggers validation before serialization
Started converting from simple string-based validators over to implementing validation classes.
Added documentation.
Renamed veritrans package to veritranspay
Moved tests for the 5 base validators into their own module and refactored the RequiredValidator tests
Added live api tests
Renamed dummy_data to fixtures
Updated response handler to accept 200 or 201 responses
Merge branch 'master' of github.com:derekjamescurtis/veritranspay