Initial implementation of pyexpat

Fix failure -- use PyStrRef to extract String.

Add test_socket

Bump addressable from 2.7.0 to 2.8.0

Bumps [addressable](https://github.com/sporkmonger/addressable) from 2.7.0 to 2.8.0.
- [Release ...

Add test_xml_dom_minicompat from CPython 3.8

Add test_xdrlib from CPython 3.8

math: raise OverflowError when result is infinite

Matches CPython behavior.

Fix iteration issues, pickling by marking iterators as exhausted.

Make `frozenset(empty_iterable)` return a singleton.

Add test_webbrowser from CPython 3.8

Add test_wsgiref from CPython 3.8

Suggestion: remove PEP 594 "dead batteries" from whats_left.sh

Add test_weakref from CPython 3.8

Add test_weakset from CPython 3.8

Add test_uu from CPython 3.8

Change `os.rs` to build on musl libc

Add test_utf8source from CPython 3.8

Add test_utf8_mode

Add test_userlist from CPython 3.8

os: Implement getgroups

os: Implement (f)pathconf

Add test_userstring from CPython 3.8

Lib: Update operator.py to follow CPython's implementation

Fix a number of range issues.

Fix test_vars in test_builtins.

Make tuple(empty_iterable) return empty_tuple

Please clippy.

Add new and bool for NotImplemented.

New simply returns the singleton. While `bool(NotImplemented)` already
returned `True`, it is ad...

Fix tests in os

Fix miscalculation when reversing a range.

Implement pathconf and fpathconf using libc::pathconf.

os.pathconf_names is not implemented.

`getgroups` is already implement in rust, just wrap the function
to let it be used in python.

Use a Utf8size struct to represent the {bytes,chars} pairs in textio

Fallback to __name__ if __qualname__ isn't available.