Server render the main page

Also, add hashes to asset file names and use the "entry manifest" plugin
in dev to get auto-reloading.

public/systemjs@2.0.0/dist/extras/transform.js

@@ -0,0 +1,32 @@
+/*
+ * Support for a "transform" loader interface
+ */
+(function () {
+  const systemJSPrototype = System.constructor.prototype;
+
+  const instantiate = systemJSPrototype.instantiate;
+  systemJSPrototype.instantiate = function (url, parent) {
+    if (url.slice(-5) === '.wasm')
+      return instantiate.call(this, url, parent);
+
+    const loader = this;
+    return fetch(url)
+    .then(function (res) {
+      if (!res.ok)
+        throw new Error('Fetch error: ' + res.status + ' ' + res.statusText + (parent ? ' loading from  ' + parent : ''));
+      return res.text();
+    })
+    .then(function (source) {
+      return loader.transform.call(this, url, source);
+    })
+    .then(function (source) {
+      (0, eval)(source + '\n//# sourceURL=' + url);
+      return loader.getRegister();
+    });
+  };
+
+  // Hookable transform function!
+  systemJSPrototype.transform = function (_id, source) {
+    return source;
+  };
+})();