Implement automatic type register mechanism that stores all speckle Base model subclasses in a type
register for deserialization reuse in transports. This enables the Base to be useful as a base kit
object.
fix#50
It was possible to override the builint types with a duplicate speckle_type, either via a duplicate
class name of an explicit speckle_type definition. It is now checked before registering the new type
in the subclass registry, and a meaningful error is thrown.
izzy lyseggen