Cleanups on 8x8 grid processing examples:

* All ported examples have been fixed (resizing);
* The particle FFT have been improved (sinusoidale pulsation,
  particles movements based on FFT filter).

Signed-off-by: Piment Noir Task Force <elecdev@piment-noir.org>
Tuning on the dancing particles processing example.

Signed-off-by: Piment Noir Task Force <elecdev@piment-noir.org>