Using unpinned versions in setup.py

The rational is to avoid getting in the way of the various
tools that force their own pinning.

pip-requirements.txt give the versions we've been testing,
but people are free to try other combos on their own.

prepping for 0.6

make sure setup.py does not depend on any lib circus uses

make sure setup.py does not depend on any lib circus uses

Bump to 0.5.1

fixed a test

updated the CHANGES for 0.4

prepping 0.3.4

prep for 0.3.3

prep for 0.3.2