add vr model demo

Demos.md

@@ -26,6 +26,14 @@ Demos are included in `/demo`:
 - `nodejs/node-webcam`: [nodejs]  
   Processing of webcam screenshots using `fswebcam`
 
+## External Demos
+
+- `Human-VRM`  
+  VR model with head, face, eye, body and hand tracking  
+  Using [`three`](https://github.com/mrdoob/three.js) for 3D display and scene management and [`@pixiv/three-vrm`](https://github.com/pixiv/three-vrm) for VR model mapping  
+  [Code](https://github.com/vladmandic/human-vrm) | [Demo](https://vladmandic.github.io/human-vrm/src/human-vrm.html)
+
+
 <br><hr><br>
 
 ## Main Demo