As IE does not support EXT_frag_depth webGL extension i added a check…

… to see if it is available. If not we use another render state configuration wich solves the issue of alpha adding up, but creates another issue of depth order of points.

app/scripts/contrib/Cesium/CesiumView.js

@@ -929,7 +929,17 @@ define(['backbone.marionette',
 	            		that.activeCollections.push(obj.id);
 	            		if (settings[obj.id].band == 'F') {
 	            			that.features_collection[obj.id] = new Cesium.PointPrimitiveCollection();
-
+
+	            			if(!that.map.scene.context._gl.getExtension('EXT_frag_depth')){
+	            				that.features_collection[obj.id]._rs = Cesium.RenderState.fromCache({
+		  						    depthTest : {
+		  						        enabled : true,
+		  						        func : Cesium.DepthFunction.LESS
+		  						    },
+		  						    depthMask : false,
+		  						    blending : Cesium.BlendingState.ALPHA_BLEND
+		  						});
+	            			}
 	            		}else if(
 	            			settings[obj.id].band == 'B_NEC' ||
 	            			settings[obj.id].band == 'SIFM' ||