Add mirror routine

```
The effects of specular reflection can be approximated by a two-pass technique using the stencil buffer. During the first pass, we render the reflected image of the scene. During the second pass, we render the non-reflected view of the scene, using the stencil buffer to prevent the reflected image from being drawn over.
```
https://www.opengl.org/archives/resources/code/samples/advanced/advanced97/notes/node90.html

**It would be interesting to have a method mirror on camera**

camera.mirror(plane);
Position and direction would be reflected according to the mirror plane.

Cross product between up and plane may be useful.

LibGDX Snippet:
```
https://github.com/libgdx/libgdx/blob/master/gdx/src/com/badlogic/gdx/graphics/Camera.java#L151

Point: Intersector#intersectRayPlane
Axis:
Angle:
```

Example (JoGL Port)
http://jerome.jouvie.free.fr/opengl-tutorials/Tutorial23.php