Prepare release 1.0.4 (python#129)

Prepare release 1.0.3

Prepare 1.0.2 release

Fix runtests.py

Fix runtests.py: handle FileNotFoundError when removing
pyperformance.egg-info.

Prepare pyperformance 1.0.0 release

prepare 0.9.1 release

Increase version to 0.9 since the project name changed

Prepare 0.9 release.

Travis CI: fix PyPy version

Update changelog

Prepare 0.6.1 release