Class for grouping attributes together in a User Defined Type. The UDT
can then be reused in memory map description to avoid making multiple edits later.
The UDT is also the type required when defining a class.
The child attributes of a UDT become properties of the UDT with the same name as the
attribute. Unnamed properties will not be accessible, but any named children of the unnamed
property will become accessible from the first parent up the chain with a name.
Child attributes may be of any type that derives from cip.CIPVar, including another