change tsconfig target to es5 because issue https://github.com/Microsoft/TypeScript-Babel-Starter/issues/26

tsconfig.json

@@ -1,6 +1,6 @@
 {
     "compilerOptions": {
-        "target": "es6",
+        "target": "es5",
         "module": "commonjs",
         "downlevelIteration": true,
         "noUnusedLocals": true,