workaround for incompatibilities with gunicorn >= 0.17.0
see esp. https://github.com/benoitc/gunicorn/commit/b7b51adf13e92044211b267ba07e3498585f219a
add an ugly redundant compatibility hack to support gunicorn < 0.17.0
Merge remote-tracking branch 'datadealer/master'

Fix the comma placement at the same time.

Conflicts:
	socketio/sgunicorn.py
docs: Little space that affected the layout in the rendered docs.