Implement Disqus comments

* Add ':' between meta_title and site_title in base.html template
* Add DISQUS_HOSTNAME and DISQUS_SHORTNAME to settings
* Add Disqus div and JS to project-detail page
* Document settings in Developer docs
* Update Changelog
Merge branch 'develop' into feature/26-disqus

Fixed Conflicts:
	docs/CHANGELOG.rst
Merge branch 'develop' into feature/26-disqus
Update Changelog and include Caleb's fixes
Merge pull request #190 from python/feature/26-disqus

Implement Disqus comments