Added using UnityEngine; to UpdateInputManager

using UnityEngine; needs to be added the the UpdateInputManager demo otherwise Unity throws an error saying "The type or namespace name `MonoBehaviour' could not be found. Are you missing a using directive or an assembly reference?"
Merge pull request #25 from RyanNielson/patch-1

Update README.md.
Merge branch 'refs/heads/develop'
Solution updates.