Speed improvements for typing (#439)

* Inline _geqv and _gorg

* Fix typo

* Cut MROs in half

* Avoid recursion on _gorg

* Fix lint

* Fxi lint (for realz)

* Refactor erasure logic to make it clearer (and probably faster)

* Remove redundant check

* Remove unnecessary comment

* Backport first part to Python 2

* Backport second part to Python 2

* Keep only obvious speed-ups and drop more aggressive optiomizations

* Fix _Protocol on Python 2

* Address CR
2 files changed