Better type support with components

Currently the way records and variants are supported with components is a bit kludge. All records are a `Record` and some variants are a `Variant` but others are "a union of a bunch of types". There's no way to get more static information which is unfortunate.

Ideally what would happen is that when a component was loaded and compiled it would load up and define Python classes for variants/records within the component. These python classes would then be used during conversion to/from C and could be used with `isinstance` and such. In theory it would also be nice to customize the classes used for use cases like ahead-of-time generated bindings.