Fixes for create, DateTime parsing
Allow primary_key to be set on create
Active Record allows the primary key to be set on create. Active Remote now behaves the same way by allowing the primary key attribute to be sent in a create operation. [#61, @mattnichols]
Handle invalid DateTime attributes gracefully
The Date typecaster will gracefully handle invalid dates, but DateTime did not. Change the behavior of DateTime types to match the behavior of Date types. [#62, @brianstien]