- Zap various occurrences of Python2 in docs and scripts
- Remove six from netlib, and some other places where obvious project-wide
search and replace works.
- Move more stuff that belongs in netlib.human
- Move some stuff to near the only use
- Zap mitmproxy.utils.timestamp(). I see the rationale, but we used it
interchangeably with time.time() throughout the project. Since time.time()
dominates in the codebase and timestamp() is such low utility, away it goes.
