change models
merge models and services
add updateble attribute, change services
add missing files
add validation and fix payments service with async
add response codes and fix json serializaion of Interval
fix services with async methods, refactor models, add comment fo factory methods
factory methods for Transactions
fix serilization of multiple and single results
add more tests for refunt, transactions, preauth
add tests for subscriptions and fixed urlencode
fix tests and bugs
add snake atribute, prepare query methods, change AbstractService for new list methods
done with client's filters
refactor filters to have base class
add payments filters
add filters for preauthorization
Add filters for webhook, refund, transaction, subscription.
add enums as class to avoid crash on serialization
remove old Sandbox and edit read me