Cesium version b8 released.

[Daniel Bagnell]

Hi all,

Cesium version b8 has been released and is available for download.

Some highlights of the release:

• Added Fabric, a JSON schema for describing materials in Cesium. See the Fabric wiki for more details.
• Added support for CZML path visualization via the `DynamicPath` and `DynamicPathVisualizer` objects. See the CZML Guide for details.
  
• Added support for nested polygons with holes.
  
• Added support to the renderer for view frustum and central body occlusion culling.
  

For a list of all of the changes, see the change log.

Regards,

Dan