Disabled antialias for examples that use full-screen postprocessing.

It doesn't have effect there anyway as scene is rendered to FBO without multisampling.

Turning antialiasing off here didn't have much effect on performance though (unlike for particles).

examples/webgl_postprocessing.html

@@ -184,7 +184,7 @@
 				quadScreen.position.z = -100;
 				sceneScreen.addObject( quadScreen );
 
-				renderer = new THREE.WebGLRenderer();
+				renderer = new THREE.WebGLRenderer( { antialias: false } );
 				renderer.setSize( window.innerWidth, window.innerHeight );
 				renderer.autoClear = false;
 				container.appendChild( renderer.domElement );