Found out that CrosseyedWebGLRenderer probably wouldn't work for target-less cameras.
Something weird going on with `webgl_scene_test.html` and `webgl_scene_test_blender.html`. For some reason cubes dissapear.
This allows, for example, better integration of additively blended materials with a regular scene.
Not to be confused with depthTest (which controls complete access to depth buffer, including reading).
Also messed up a bit with particle emitter example.