- Removed the camera 'mode'
    - The (old) static camera was only appropriate when parallel
      projection was inactive, and the view was centred at (0 0 0)
    - Camera input now always requires 'position' and 'focalPoint'
    - Clip box is now optional.  Note that this is applied after the
      camera
      set-up and so will override the camera position
    - View angle is only appropriate when not using parallel projection
    - Zoom now required, applied after all other operations
      - 1 = do nothing, >1 = zoom in, <1 = zoom out

    Example input:

        camera
        {
            // Total number of frames to generate
            nFrameTotal 1;

            // Parallel projection flag
            parallelProjection no;

            // Optional clippling box
            clipBox     (-0.0206 -0.0254 -0.0005) (0.29 0.0254 0.0005);
            focalPoint  (0 0 0);
            up          (0 1 0);
            position    (0 0 1);
            viewAngle   20;
            zoom        1.1;
        }