Improvements to processing video examples :

* keyboard movie control;
* reduce pyramid array size on grid8x8 to avoid too much bluring on the video
  (TODO: should be tunable).

Signed-off-by: Piment Noir Task Force <elecdev@piment-noir.org>
Fix submodule target path in the server Makefile.

Signed-off-by: Jérôme Benoit <jerome.benoit@grenouille.com>