Update Whats New.

dist/preview release/what's new.md

@@ -124,6 +124,7 @@
 - Fixed support for R and RG texture formats ([sebavan](http://www.github.com/sebavan))
 - Fixed `updatable` parameter setting in the SPS ([jerome](https://github.com/jbousquie))
 - Angular and linear velocity were using the wrong method to copy values to the physics engine ([RaananW](https://github.com/RaananW))
+- Fixed env texture generation in Byte Mode ([sebavan](http://www.github.com/sebavan))
 
 ### Viewer