So I got tired of not having any reasonable metrics library, because scales

* uses a thread for the decay ticker, which breaks it if you use Tornado with fork()

* uses "clever tricks" and gets frisky with stack-frames to figure out the metric paths; needless to say, this breaks in weird ways, including if you use @staticmethod

* is basically Java and flake8 gives you over 9000 warnings

Any feedback welcome and much appreciated, PRs even more so.