StructuralMetadata class

This class provides support for EXT_structural_metadata, only used in glTF.

The StructuralMetadata type exposes the following members:

Constructor	Description
`__init__(self)`	Constructs a new instance of StructuralMetadata

Property	Description
property_tables	The property tables in this metadata.

Method	Description
`create_class(self, name)`	Create a meta class type
`create_enum(self, name)`	Create an enum type
`create_property_table(self, name, clazz)`
`attach(self, scene)`	Attach current meta data to specified scene
`from_address(, scene)`	Get `StructuralMetadata` associated with specified scene.