Update history for next release

Change-Id: Ibc424639b06362ce915776ea5914860e809ce25e
add venv environ to tox config

Change-Id: I9c2091ccac212e7bd8f5f6af571426dd10a1d18e
move to pbr for packaging

Change-Id: I93e4f54d1b81f53615774aa5f79b3e6a9941a55d