fix(tsconfig): app.ts is main.ts now

fixes TSError `file not included in the typescript compilation context`
(#461)

Author: Ionut

addon/ng2/blueprints/ng2/files/src/client/tsconfig.json

@@ -17,7 +17,7 @@
   },
 
   "files": [
-    "app.ts",
+    "main.ts",
     "typings.d.ts"
   ]
 }