Add detection of github pages (#1866)

* Add detection of github pages

This can be tested [here](http://www.sxcurity.pro/2017/11/27/tricky-CORS/).

* s/svg/png/

* Take @q-- comments into account ♥

src/apps.json

@@ -3045,6 +3045,20 @@
 			},
 			"website": "http://gitbook.io"
 		},
+		"GitHub Pages": {
+			"cats": [
+				"11",
+				"31"
+			],
+			"url": "^https?://[^/]+\\.github\\.io/",
+			"headers": {
+				"Server": "^GitHub\\.com$",
+				"X-GitHub-Request-Id": ""
+			},
+			"icon": "GitHub.svg",
+			"implies": "Ruby on Rails",
+			"website": "https://pages.github.com/"
+		},
 		"GitLab": {
 			"cats": [
 				"13",

src/icons/GitHub.svg

@@ -0,0 +1,35 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<svg
+   xmlns:dc="http://purl.org/dc/elements/1.1/"
+   xmlns:cc="http://creativecommons.org/ns#"
+   xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
+   xmlns:svg="http://www.w3.org/2000/svg"
+   xmlns="http://www.w3.org/2000/svg"
+   id="svg215"
+   version="1.1"
+   viewBox="0 0 11.493 11.493"
+   height="11.493mm"
+   width="11.493mm">
+  <defs
+     id="defs209" />
+  <metadata
+     id="metadata212">
+    <rdf:RDF>
+      <cc:Work
+         rdf:about="">
+        <dc:format>image/svg+xml</dc:format>
+        <dc:type
+           rdf:resource="http://purl.org/dc/dcmitype/StillImage" />
+        <dc:title></dc:title>
+      </cc:Work>
+    </rdf:RDF>
+  </metadata>
+  <g
+     transform="translate(0,-285.507)"
+     id="layer1">
+    <path
+       id="path16"
+       style="fill:#1b1817;fill-opacity:1;fill-rule:evenodd;stroke:none;stroke-width:0.03527778"
+       d="M 5.74605,285.64853 C 2.57317,285.64853 0,288.22134 0,291.39528 c 0,2.53859 1.64642,4.69265 3.92995,5.45289 0.28751,0.0526 0.39229,-0.12488 0.39229,-0.27728 0,-0.13653 -0.005,-0.49777 -0.008,-0.9772 -1.59844,0.34713 -1.93569,-0.77046 -1.93569,-0.77046 -0.26141,-0.66393 -0.63818,-0.84067 -0.63818,-0.84067 -0.52176,-0.35631 0.0395,-0.34925 0.0395,-0.34925 0.57679,0.0406 0.88018,0.59231 0.88018,0.59231 0.51259,0.87806 1.34514,0.62442 1.67252,0.47731 0.0522,-0.37112 0.20073,-0.62442 0.36477,-0.768 -1.27599,-0.14534 -2.61761,-0.63817 -2.61761,-2.84021 0,-0.62759 0.22402,-1.14018 0.59161,-1.54199 -0.0593,-0.14535 -0.25647,-0.72955 0.0565,-1.52083 0,0 0.48224,-0.15452 1.58009,0.58879 0.45826,-0.12736 0.95003,-0.19086 1.43863,-0.19333 0.48824,0.002 0.97966,0.066 1.43862,0.19333 1.09714,-0.74331 1.57868,-0.58879 1.57868,-0.58879 0.31362,0.79128 0.11642,1.37548 0.0575,1.52083 0.3683,0.40181 0.59055,0.9144 0.59055,1.54199 0,2.20768 -1.34373,2.69346 -2.62361,2.83562 0.20602,0.17745 0.38982,0.52811 0.38982,1.06434 0,0.76799 -0.007,1.38782 -0.007,1.57621 0,0.15381 0.10371,0.33267 0.39511,0.27657 2.28177,-0.76164 3.92677,-2.91394 3.92677,-5.45218 0,-3.17394 -2.57316,-5.74675 -5.7471,-5.74675" />
+  </g>
+</svg>