Add generator meta tag

lib/static/Html.js

@@ -16,6 +16,7 @@ module.exports = ({
   h('head', null,
     h('title', null, title),
     h('meta', { charSet: 'utf-8' }),
+    h('meta', { name: 'generator', content: 'Compositor x0' }),
     meta('viewport', 'width=device-width, initial-scale=1'),
     meta('description', description),
     image && meta('og:image', image),