Merge pull request #756 from jbousquie/patch-1

Update what's new.md

dist/preview release/what's new.md

@@ -1,5 +1,6 @@
 - 2.3.0:
   - **Major updates**
+    - New Solid Particle System ([jerome](https://github.com/jbousquie))
     - New `StandardMaterial.lightmapTexture` which can be controlled with `StandardMaterial.lightmapThreshold`. [Demo here](#NEEDDEMO) ([deltakosh](https://github.com/deltakosh))
     - Support for reflection probes. [See documentation here](http://doc.babylonjs.com/tutorials/How_to_use_Reflection_probes) ([deltakosh](https://github.com/deltakosh))
     - New serializers [folder](https://github.com/BabylonJS/Babylon.js/serializers) to host .babylon serializers ([deltakosh](https://github.com/deltakosh))