v0.18.2
Fixed bug in email Message.set_boundary() Also added tests that would expose the bug.
Trim trailing white space throughout the project
fix collections abc import for py38
Revert "allow mixed string type inputs to misc urllib.parse.* functions"
Move all source code to src/
Future-proof for Py4.0
Fix several warnings
Use the same sentinel as in the stdlib ``socket.py`` for ``create_connection()`` in ``future.backports.socket``