Merge tag 'sparks-2.6.16' into develop

2.6.16
Make install work again on OSX. It's been time since I used it.
Adapt a part for Ubuntu 13.*.
Do not assume is_local…() to avoid running collectstatic, but better instead: test if remote environment has DEBUG=True, in which case Django is much more likely to serve static files directly.
Create the virtualenv even in local mode. This helps first `tunable`.
bump version in setup.py
Merge branch 'release/2.6.17'