Allow CSS, JS, and meta to be defined in the header of any page
Tweak "index_of" page

Now it behaves more like a plugin.

Also removed extra arrow in "More" snippet (it was required in an older
version)
Use 'page.style' instead of 'page.layout'

The value for 'layout' is unreliable, and depends heavily on when the
value is retrieved.
In snippets, use the name 'local' instead of 'name'

It's clearer, plus I may have plans for 'name' in the future.
Add 'minimal' option to the Slate theme

This results in a tiny header and footer, so as to not distract from the
page content.
Move 'slate' stylesheet imports to separate file
Merge 'v0.4' into gh-pages-minimal

Version v0.4

Primary addition is the new Slate minimalist template.

Conflicts:
	_config.yml