Allow bytecode again (#9502)

In #75, bytecode was disabled (from a bit of FUD back in `python<2.4` days, according to dev chat), I think it's safe enough to enable it again.

Added in `__pycache__/` and `.pyc`/`.pyd` to `.gitignore`, to extra-insure compiled files don't get committed.

`Signed-off-by: Jonathan de Jong <jonathan@automatia.nl&gt;`>