offer a consistent decorator-ish API for the functionality of pure_http
simplify to just use *args and **kwargs so we don't need to care about every arg
make the names of auth-related functions more general and not mention auth except in docstrings
Merge pull request #730 from rackerlabs/pure-http-refinements

pure_http refinements and "bind_root"
Merge branch 'master' into rcv3-steps
Shortest, unambiguous step names

Thanks @cyli!