build: add ng as a package binary

So that "npm link" will install it globally.

Author: hansl

bin/ng

@@ -6,6 +6,7 @@
     "architect": "./bin/architect",
     "build-optimizer": "./bin/build-optimizer",
     "devkit-admin": "./bin/devkit-admin",
+    "ng": "./bin/ng",
     "purify": "./bin/purify",
     "schematics": "./bin/schematics"
   },