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

docs/_pages/home.md

@@ -0,0 +1,38 @@
+---
+layout: splash
+permalink: /
+header:
+  overlay_color: "#5e616c"
+  overlay_image: /assets/images/mm-home-page-feature.jpg
+  cta_label: "<i class='fa fa-download'></i> Install Now"
+  cta_url: "/docs/quick-start-guide/"
+  caption:
+excerpt: 'A flexible two-column Jekyll theme. Perfect for personal sites, blogs, and portfolios hosted on GitHub or your own server.<br /> <small><a href="https://github.com/mmistakes/minimal-mistakes/releases/tag/4.0.4">Latest release v4.0.4</a></small><br /><br /> {::nomarkdown}<iframe style="display: inline-block;" src="https://ghbtns.com/github-btn.html?user=mmistakes&repo=minimal-mistakes&type=star&count=true&size=large" frameborder="0" scrolling="0" width="160px" height="30px"></iframe> <iframe style="display: inline-block;" src="https://ghbtns.com/github-btn.html?user=mmistakes&repo=minimal-mistakes&type=fork&count=true&size=large" frameborder="0" scrolling="0" width="158px" height="30px"></iframe>{:/nomarkdown}'
+feature_row:
+  - image_path: /assets/images/mm-customizable-feature.png
+    alt: "customizable"
+    title: "Super Customizable"
+    excerpt: "Everything from the menus, sidebars, comments, and more can be configured or set with YAML Front Matter."
+    url: "/docs/configuration/"
+    btn_label: "Learn More"
+  - image_path: /assets/images/mm-responsive-feature.png
+    alt: "fully responsive"
+    title: "Responsive Layouts"
+    excerpt: "Built on HTML5 + CSS3. All layouts are fully responsive with helpers to augment your content."
+    url: "/docs/layouts/"
+    btn_label: "Learn More"
+  - image_path: /assets/images/mm-free-feature.png
+    alt: "100% free"
+    title: "100% Free"
+    excerpt: "Free to use however you want under the MIT License. Clone it, fork it, customize it, whatever!"
+    url: "/docs/license/"
+    btn_label: "Learn More"
+github:
+  - excerpt: '{::nomarkdown}<iframe style="display: inline-block;" src="https://ghbtns.com/github-btn.html?user=mmistakes&repo=minimal-mistakes&type=star&count=true&size=large" frameborder="0" scrolling="0" width="160px" height="30px"></iframe> <iframe style="display: inline-block;" src="https://ghbtns.com/github-btn.html?user=mmistakes&repo=minimal-mistakes&type=fork&count=true&size=large" frameborder="0" scrolling="0" width="158px" height="30px"></iframe>{:/nomarkdown}'
+intro:
+  - excerpt: 'Get notified when I add new stuff &nbsp; [<i class="fa fa-twitter"></i> @mmistakes](https://twitter.com/mmistakes){: .btn .btn--twitter}'
+---
+
+{% include feature_row id="intro" type="center" %}
+
+{% include feature_row %}