message: Improve TFLite iOS doc.
diff: -# TensorFlow Lite for iOS
  +# Build TensorFlow Lite for iOS
  +
  +This document describes how to build TensorFlow Lite iOS library. If you just
  +want to use it, the easiest way is using the TensorFlow Lite CocoaPod releases.
  +See [TensorFlow Lite iOS Demo](demo_ios.md) for examples.
  +
  ## Building
  