Account type detection

[stockh4]

Hi Brian - thanks for this script - really saved me a lot of time.

Long-term, we could think about algorithmically tagging wallets by account / user types. There are a few papers out with methodologies. This is just an idea for the very long term -- it would be helpful for us to work towards having this kind of taxonomy on Ethereum data. I wonder what Etherscan itself has on its roadmap. It seems like such a basic and necessary resource. I see several teams doing this for their own projects all over again each time.

Great job so far - just leaving a note. New to Github. Thanks again! Much appreciate your work.