Pin / upgrade (almost) all Python packages (fixes #496)
Pin / upgrade (almost) all Python packages (fixes #496)

Pin and upgrade all Python package to their current version in PyPI
except:

- Sphinx (because a prelease would be pulled)
- autobahn (because 0.9.3 breaks a test in `websockets/test_server.py`)

Notable upgrades:

- pyramid: 1.5.1 -> 1.5.2
- ZODB / ZEO: 4.0.x -> 4.1.0
- colander: 1.0b1 -> 1.0
- websocket-client: 0.18.0 -> 0.23.0

- flake8: 2.2.3 -> 2.3.0
- mccabe: 0.2.1 -> 0.3

fhartwig/adhocracy3.mercator,fhartwig/adhocracy3.mercator,liqd/adhocracy3.mercator,xs2maverick/adhocracy3.mercator,xs2maverick/adhocracy3.mercator,liqd/adhocracy3.mercator,xs2maverick/adhocracy3.mercator,liqd/adhocracy3.mercator,liqd/adhocracy3.mercator,fhartwig/adhocracy3.mercator,liqd/adhocracy3.mercator,fhartwig/adhocracy3.mercator,fhartwig/adhocracy3.mercator,fhartwig/adhocracy3.mercator,liqd/adhocracy3.mercator,xs2maverick/adhocracy3.mercator,liqd/adhocracy3.mercator,fhartwig/adhocracy3.mercator,xs2maverick/adhocracy3.mercator,xs2maverick/adhocracy3.mercator