fix missing last log line

Sometimes calls to app.err.Fatalf would fail to print the error to the
console, and fail to show "A crash report has been saves to...". Both of
these should be fixed now.

package.json

@@ -29,5 +29,8 @@
     "remove-markdown": "^0.3.0",
     "typescript": "^4.0.3",
     "uncss": "^0.17.3"
+  },
+  "devDependencies": {
+    "live-server": "^1.2.1"
   }
 }