Merge pull request #4700 from AnalyticalGraphicsInc/float-texture-fall-back

Remove floating-point texture requirement

Author: pjcozzi

CHANGES.md

@@ -11,6 +11,7 @@ Change Log
    * `TextureAtlas.borderWidthInPixels` has always been applied to the upper and right edges of each internal texture, but is now also applied to the bottom and left edges of the entire TextureAtlas, guaranteeing borders on all sides regardless of position within the atlas.
 * Added support for saving html and css in GitHub Gists. [#4125](https://github.com/AnalyticalGraphicsInc/cesium/issues/4125)
 * Fixed `Cartographic.fromCartesian` when the cartesian is not on the ellipsoid surface. [#4611](https://github.com/AnalyticalGraphicsInc/cesium/issues/4611)
+* Fall back to packing floats into an unsigned byte texture when floating point textures are unsupported. [#4563](https://github.com/AnalyticalGraphicsInc/cesium/issues/4563)
 
 ### 1.27 - 2016-11-01
 * Deprecated