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/assets/images/manifest.json

@@ -0,0 +1,41 @@
+{
+	"name": "Minimal Mistakes",
+	"icons": [
+		{
+			"src": "\/images\/android-chrome-36x36.png?v=M44lzPylqQ",
+			"sizes": "36x36",
+			"type": "image\/png",
+			"density": 0.75
+		},
+		{
+			"src": "\/images\/android-chrome-48x48.png?v=M44lzPylqQ",
+			"sizes": "48x48",
+			"type": "image\/png",
+			"density": 1
+		},
+		{
+			"src": "\/images\/android-chrome-72x72.png?v=M44lzPylqQ",
+			"sizes": "72x72",
+			"type": "image\/png",
+			"density": 1.5
+		},
+		{
+			"src": "\/images\/android-chrome-96x96.png?v=M44lzPylqQ",
+			"sizes": "96x96",
+			"type": "image\/png",
+			"density": 2
+		},
+		{
+			"src": "\/images\/android-chrome-144x144.png?v=M44lzPylqQ",
+			"sizes": "144x144",
+			"type": "image\/png",
+			"density": 3
+		},
+		{
+			"src": "\/images\/android-chrome-192x192.png?v=M44lzPylqQ",
+			"sizes": "192x192",
+			"type": "image\/png",
+			"density": 4
+		}
+	]
+}