Move gh-pages branch files into /docs and add test files

- Jekyll ignore `/docs` and `/test` folders when using from root
- Update Staticman config to point to correct branch and data file location
- Replace `{{ base_path }}` references with `absolute_url` filter
- Update documentation

test/_posts/2012-01-02-layout-comments-disabled.md

@@ -0,0 +1,14 @@
+---
+title: "Layout: Comments Disabled"
+comments: false
+categories:
+  - Layout
+  - Uncategorized
+tags:
+  - comments
+  - layout
+---
+
+This post has its comments disabled.
+
+There should be no comment form.