added helpful makefile
flake8 fixes
reformatted changelog
fixed __pycache__ cleaner in Makefile
changelog should use tabs
watch mode for tests
added instance_method support to memoize

 * memoize now takes instance_method=True
 * if it is true, memoize will make a cache per class instance
import __version__ is more obv
added timer context manager
Release: Wraptor v0.4.0
try allowing 2 ms of fudge room on the timer