Removed SITE_NAME setting

Not really needed
Use "restart" command instead of supervisorctl
Added puppet configuration
Added .pp to list of template extensions
CSSMin required for production css minification middleware
added HTMLmin
Bumped Wagtail version to 0.8.3
Removed cssmin from pip requirements

This seems to be bundled with Django compressor:
https://github.com/django-compressor/django-compressor/blob/develop/compressor/filters/cssmin/cssmin.py

The original cssmin (now unmaintained):
https://github.com/zacharyvoase/cssmin/blob/master/src/cssmin.py
Update Wagtail version to 0.8.4