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/2013-01-05-markup-title-with-markup.md

@@ -0,0 +1,14 @@
+---
+title: "Markup: Title *with* **Markdown**"
+categories:
+  - Markdown
+tags:
+  - css
+  - html
+  - title
+---
+
+Verify that:
+
+* The post title renders the word "with" in *italics* and the word "Markdown" in **bold**.
+* The post title markup should be removed from the browser window / tab.