removed unused code in alphaWeight.glsl, fixed curly braces to follow code style
removed unused code in alphaWeight.glsl, fixed curly braces to follow code style

likangning93/cesium,soceur/cesium,likangning93/cesium,geoscan/cesium,hodbauer/cesium,kaktus40/cesium,hodbauer/cesium,CesiumGS/cesium,jasonbeverage/cesium,likangning93/cesium,josh-bernstein/cesium,soceur/cesium,YonatanKra/cesium,geoscan/cesium,AnalyticalGraphicsInc/cesium,jasonbeverage/cesium,CesiumGS/cesium,YonatanKra/cesium,likangning93/cesium,progsung/cesium,likangning93/cesium,CesiumGS/cesium,YonatanKra/cesium,josh-bernstein/cesium,AnalyticalGraphicsInc/cesium,progsung/cesium,soceur/cesium,CesiumGS/cesium,hodbauer/cesium,YonatanKra/cesium,kaktus40/cesium,CesiumGS/cesium