Save changes for next version
Create Business::CPI::Util namespace
Move classes to roles

This is a massive change. Roles will allow more flexibility, and will
help organize the namespace. Most drivers will break after this.
Create utility to load classes dynamically

Create class Business::CPI::Util for general purpose functions. Also,
create the subroutine load_class, which removes Class::Load's
"load_first_existing_class" from all over the place.
Stop documenting BUILDARGS
Document Business::CPI::Util
Split Business::CPI::Gateway::Base into a couple of roles
Use a decent type system