Remove type_dict and related logic

[rozyczko]

Weakref-ed dictionaries have been a source of constant issues. Given that the new base classes don't use those dictionaries, we should consider removing them and simplifying the logic.

[damskii9992]

With the final class using them being deprecated in #242 , we can finally move forward on this once we make another release. As we need at least 1 release where the classes has been deprecated before finally removing them.