Add favicon

I used the logo image on the site to generate a favicon using
[Real
Favicon Generator tool](http://realfavicongenerator.net/).

docs/_includes/head.html

@@ -2,6 +2,18 @@
 <meta http-equiv="X-UA-Compatible" content="IE=edge">
 <meta name="viewport" content="width=device-width, initial-scale=1">
 
+<link rel="apple-touch-icon" sizes="57x57" href="/images/apple-touch-icon-57x57.png?v=699Nxpjr2A">
+<link rel="apple-touch-icon" sizes="60x60" href="/images/apple-touch-icon-60x60.png?v=699Nxpjr2A">
+<link rel="apple-touch-icon" sizes="72x72" href="/images/apple-touch-icon-72x72.png?v=699Nxpjr2A">
+<link rel="icon" type="image/png" href="/images/favicon-32x32.png?v=699Nxpjr2A" sizes="32x32">
+<link rel="icon" type="image/png" href="/images/favicon-16x16.png?v=699Nxpjr2A" sizes="16x16">
+<link rel="manifest" href="/images/manifest.json?v=699Nxpjr2A">
+<link rel="mask-icon" href="/images/safari-pinned-tab.svg?v=699Nxpjr2A" color="#F6F6F6">
+<link rel="shortcut icon" href="/images/favicon.ico?v=699Nxpjr2A">
+<meta name="msapplication-TileColor" content="#da532c">
+<meta name="msapplication-config" content="/browserconfig.xml?v=699Nxpjr2A">
+<meta name="theme-color" content="#f6f6f6">
+
 <title>
   {{ page.title }}
 </title>

docs/browserconfig.xml

@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="utf-8"?>
+<browserconfig>
+  <msapplication>
+    <tile>
+      <square70x70logo src="/images/mstile-70x70.png?v=699Nxpjr2A"/>
+      <square150x150logo src="/images/mstile-150x150.png?v=699Nxpjr2A"/>
+      <wide310x150logo src="/images/mstile-310x150.png?v=699Nxpjr2A"/>
+      <TileColor>#da532c</TileColor>
+    </tile>
+  </msapplication>
+</browserconfig>

docs/images/manifest.json

@@ -0,0 +1,23 @@
+{
+	"name": "Select2",
+	"icons": [
+		{
+			"src": "\/images\/android-chrome-36x36.png?v=699Nxpjr2A",
+			"sizes": "36x36",
+			"type": "image\/png",
+			"density": 0.75
+		},
+		{
+			"src": "\/images\/android-chrome-48x48.png?v=699Nxpjr2A",
+			"sizes": "48x48",
+			"type": "image\/png",
+			"density": 1
+		},
+		{
+			"src": "\/images\/android-chrome-72x72.png?v=699Nxpjr2A",
+			"sizes": "72x72",
+			"type": "image\/png",
+			"density": 1.5
+		}
+	]
+}

docs/images/safari-pinned-tab.svg

@@ -0,0 +1,17 @@
+<?xml version="1.0" standalone="no"?>
+<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 20010904//EN"
+ "http://www.w3.org/TR/2001/REC-SVG-20010904/DTD/svg10.dtd">
+<svg version="1.0" xmlns="http://www.w3.org/2000/svg"
+ width="72.000000pt" height="72.000000pt" viewBox="0 0 72.000000 72.000000"
+ preserveAspectRatio="xMidYMid meet">
+<metadata>
+Created by potrace 1.11, written by Peter Selinger 2001-2013
+</metadata>
+<g transform="translate(0.000000,72.000000) scale(0.100000,-0.100000)"
+fill="#000000" stroke="none">
+<path d="M177 598 l-179 -120 86 -57 c47 -31 86 -59 86 -63 0 -3 -39 -32 -86
+-63 l-86 -58 181 -119 181 -119 181 122 180 121 -82 54 c-46 30 -84 56 -86 58
+-3 2 21 21 52 42 31 22 70 49 86 61 l30 21 -180 121 c-99 67 -181 121 -183
+120 -2 0 -83 -54 -181 -121z"/>
+</g>
+</svg>