use serializemembers function

[JohnHeikens]

serializemembers can't be used (return self.dict or looping over struct members) because:

• dict also returns derived members
• dict will return complex members like a point object as-is, so without calling dict on that object
• deserializing as dict will make the program very vulnerable
• https://www.marcstober.com/blog/2007/07/07/serializing-arbitrary-python-objects-to-json-using-__dict__/

deriving from dict itself isn't recommended

[JohnHeikens]

find a way to implement a serialization function which can use dict for directly serializable members, and for the rest calls a custom serialization function

[JohnHeikens]

for now, we are using this trick: serialized_data = json.dumps(self.objects, default=lambda x: getattr(x, 'dict', str(x)))

[JohnHeikens]

serialization is working! the already defined functions can still be used