PEP8 compliance, gitignore cache/ and data/ dirs, use argparse

PEP8 compliance because I'm obsessive compulsive!

Switch to argparse for command line goodness.

I also noticed that cache/ and data/ were ignored if they were in the scripts directory, but if the scraper is run from the project root then cache/ and data/ show as untracked. Updated .gitignore to make it ignore those directories no matter where they exist in the project tree.