Make it possible to subclass more types
Make it possible to subclass more types

Expand the subclass support to more native types, and also make it
easier to add more in the future.

qur/gopy,qur/gopy,limetext/gopy,qur/gopy,ericsnowcurrently/qur-gopy,ericsnowcurrently/qur-gopy,limetext/gopy,limetext/gopy,ericsnowcurrently/qur-gopy