Unity Third Person Controller integration

This script allows for integration with Unity's own Third Person Controller, which is included in their own Standard Assets package. It can be used to move a character with both Direct and Point And Click methods, using the Third Person Controller script.

To use it:
 * 1) Take the existing ThirdPersonController or AIThirdPersonController prefab, and remove any existing control script (with ThirdPersonController, this is ThirdPersonUserControl; with AIThirdPersonController, this is AICharacterControl).
 * 2) Attach either AC's Player or NPC component
 * 3) In AC's Settings Manager, set your game's Movement method to either Point And Click or Direct
 * 4) Attach the script below to the character's root object
 * 5) (Optional) To allow for AC-controlled movement during e.g. cutscenes, also attach and configure a NavMeshAgent.  The scene must also rely on Unity Navigation pathfinding, as covered in the AC Manual.

UnityThirdPersonIntegration.cs: