[Speed] pymicrobench: collection of CPython microbenchmarks

[Victor Stinner]

FYI since my previous email in March, I removed the following
microbenchmarks from pyperformance to move them to pymicrobench:

* call_simple, call_method, call_method_slots, call_method_unknown
* logging_silent

pyperformance development version:
http://pyperformance.readthedocs.io/changelog.html#version-0-5-5

https://github.com/haypo/pymicrobench

Victor