Update README.md
Two small fixes.
### Volley
-Volley is an HTTP library that makes networking for Android apps easier and most
+Volley is an HTTP library that makes networking for Android apps easier and, most
importantly, faster.
-For more about Volley and how to use it, visit the [Android developer training
+For more information about Volley and how to use it, visit the [Android developer training
page](https://developer.android.com/training/volley/index.html).
