Compile express application first, than Angular 2

vladotesanovic/angular2-express-starter#73 (comment)

Author: HighQualityCode

package.json

@@ -5,7 +5,7 @@
   "main": "server/app.js",
   "license": "MIT",
   "scripts": {
-    "start": "concurrently --kill-others \"ng serve --aot=true --progress=false --proxy-config proxy.conf.json\" \"npm run _server:run\"",
+    "start": "concurrently --kill-others \"npm run _server:run\" \"ng serve --aot=true --progress=false --proxy-config proxy.conf.json\"",
     "lint:client": "ng lint",
     "lint:server": "tslint './server/**/*.ts' -c ./server/tslint.json --fix",
     "test:client": "ng test",