Fix indentation to conform to Mozilla's (and the greater community's) Python coding guidelines.

There's still a long way to go, but this at least sorts out the main thing that would cause merge conflicts for us if we were to fix it little by little. This tears off that band-aid.
Add instructions for installing the Python module to the README.

Bruce rightly ran into the situation where he hadn't done so, and things failed in non-obvious ways.