Get rid of incorrect include in demo post.
Updated to the latest version of So Simple theme
Merge branch 'update-theme'

Gets the latest So Simple theme. Note that you need to install the gem
bundler (gem install bundler) and run bundle install to get all the
dependencies that the updated theme relies on (like jekyll-sitemap).

Conflicts:
	_config.yml
	_includes/navigation.html
	_layouts/post.html
	about.md
	index.html