More Python Cleanup & Restore Wheel Building
Some of the cleanup removed a few bits that we need for the wheel building (in particular the c extension as it allows us to use repair-wheel to automatically include any library dependencies). Now I thought those where stripped and included a note motivating why they are there, but obviosuly didn't. I have added respective notes to setup.py and the extension.c files.
This also fixes a few minor documentation typos and wrong identation for a code block.