Add native value types
This branch mainly replaces the
model.base to use Python classes for all allowed data types and values of those classes instead of the XML/XSD string representation.
The parsing and serialization is handled by the
model.datatypes module and invoked by the
adapters for serialization and deserialization. Thus, a programmer using PyI40AAS in his application can work with native Python types (like int, float, bool, bytearray, str) and the framework checks type compatibility and handles serialization into the correct string representation.