[tor-dev] Updates and review on "Proposal 254: Padding Negotiation"

Hey Mike,

I took another look at prop#254 and made some changes of my own in my torspec branch circuitpadding-proposal-updates (see commit ab37543). Let me know if they look right to you. Some of those I had to look into the code to understand, and I hope I got them right.

Furthermore, I opened a pull request with a few questions and comments for further improvements and clarifications: https://github.com/torproject/torspec/pull/39

Cheers!