Author and Editor

This adds support for the "author" and "editor" tags.
Horizontal Rule

Implementation of the "horizontal" tag which spawns a horizontal line
on the page.
Images

This adds support for the "image" tag. This uses the new "images"
directory.
Added Variables and some Fixes

This adds support for the "variable" tag and some bug fixes.
Merge pull request #4 from GRAPHITE-GITHUB/v0.9-Additions

V0.9 additions