updating webvr docs to explain relation between the polyfill and three.js

aframe/examples/minecraft-launch-demo.html

@@ -25,7 +25,7 @@
 						repeat="indefinite" easing='ease-in-out-cubic'></a-animation> -->
 				</a-text>
 
-				<a-text side='double' value="So proud!" position='0.5 1.70 0' color='magenta'>
+				<a-text side='double' value="So proud!" position='0.5 1.70 0' color='magenta1'>
 					<a-animation attribute="position" from="0.6 1.1 0" to="0.6 1.3 0" direction="alternate" dur="500"
 						repeat="indefinite" easing='ease-in-out-cubic'></a-animation>
 				</a-text>

webvr-polyfill/README.md

 It is a polyfill for webvr API using artoolkit as positional tracker.
-
-- it depends on three.js
+Thus you can use the power of WebAR without depending on any specific API.
 
 
 ```html
 <!-- include artoolkit-webvr-polyfill.js -->
 <script src="artoolkit-webvr-polyfill.js"></script>
 ```
+
+# NOTES:
+- it currently depends on three.js for the maths
+  - It uses 3+ math classes Vector3/Quaternion/Matrix4...
+  - i would love it to be fully standalone but time is missing
+  - WebAR is currently a single personn effort and this is big compleex code :)
+  - the contribution is simple and a pull request
+  - if anybody is considering contributing it, i would love to help and point at the code.