allow lib/python/chashring.py to be pip installable

[cablehead]

Hi Chris,

I'd like to put together a pull request so the repo can be made available on pypi so chashring is pip installable for python users. Would you be open to this change. I'm pretty sure a setup.py is needed in the root directory of the repo, but I may be mistaken. Will do more research.

1/ Would you be open to this and
2/ Would you like to own the pypi package for chashring, or would you like me to manage that?

thanks!

[chrismoos]

I'm definitely open to this, and I'm fine if you want to maintain it on pypi.