Add VRTK to AR & VR

VRTK is a really great VR framework that has a ton of support from the community, great documention, examples, and is being maintained with fixes and awesome features.

Author: qubitz

README.md

@@ -55,6 +55,7 @@ Thanks to all the [contributors](https://github.com/ryannielson/awesome-unity/gr
 * [ARToolKit](http://artoolkit.org/documentation/doku.php?id=6_Unity:unity_about) - Augmented Reality SDK that includes libraries, utilities, and examples.
 * [Google VR SDK](https://developers.google.com/vr/unity) - Scripts and prefabs to help with the development of Google Daydream and Cardboard apps for Android and iOS.
 * [SteamVR Unity Toolkit](https://www.assetstore.unity3d.com/en/#!/content/64131) - Scripts and Great examples to abstract the use of VR controller actions in Unity.
+* [Virtual Reality Toolkit](http://github.com/thestonefox/vrtk) - Virtual Reality framework that allows for powerful interactions, locomotion, and visual effects.
 * [Vuforia](https://vuforia.com/) - Augmented Reality SDK with image and object recognition, smart terrain and extended tracking features.
 
 ## Camera