add void and rename private variable

src/PostProcess/RenderPipeline/Pipelines/babylon.defaultRenderingPipeline.ts

@@ -602,7 +602,7 @@
          * Adds a camera to the pipeline
          * @param camera the camera to be added
          */
-        public addCamera(camera:Camera){
+        public addCamera(camera:Camera):void{
             this._originalCameras.push(camera);
             this._buildPipeline();
         }
@@ -611,7 +611,7 @@
          * Removes a camera from the pipeline
          * @param camera the camera to remove
          */
-        public removeCamera(camera:Camera){
+        public removeCamera(camera:Camera):void{
             var index = this._originalCameras.indexOf(camera);
             this._originalCameras.splice(index, 1);
             this._buildPipeline();