enable AMP on more layouts/pages

layouts/_default/video.amp.html

@@ -0,0 +1,28 @@
+{{ partial "amp/head" . }}
+
+<article class="layout layout-video">
+  {{ with .OutputFormats.Get "html" }}
+  <h1 class="title"><a href="{{ .Permalink }}">{{ $.Title | markdownify }}</a></h1>
+  {{ end }}
+
+  <amp-video
+    layout="responsive"
+    width="940"
+    height="530"
+    {{ with .Resources.GetMatch "thumb.*" }}poster="{{ .Permalink }}"{{ end }}
+    controls>
+    {{ with .Page.Resources.GetMatch "*.webm" }}<source src="{{ .Permalink }}" type="video/webm">{{ end }}
+    {{ with .Page.Resources.GetMatch "*.mp4"  }}<source src="{{ .Permalink }}" type="video/mp4">{{ end }}
+    {{ with .Page.Resources.GetMatch "*.ogg"  }}<source src="{{ .Permalink }}" type="video/ogg">{{ end }}
+
+    {{ with .Page.Resources.GetMatch "*.vtt" }}<track src="{{ .Permalink }}" kind="captions" label="English" srclang="en" default>{{ end }}
+
+    <div fallback>
+      <p>Your browser does not support HTML5 video. {{ with .Page.Resources.GetMatch "*.mp4"  }}<a href="{{ .Permalink }}">Load the .mp4 video directly.</a>{{ end }}</p>
+    </div>
+  </amp-video>
+
+  {{ .Content }}
+</article>
+
+{{ partial "amp/foot" . }}