New: Statistics support filtering on user.

htdocs/comm/propal/class/propalestats.class.php

htdocs/comm/propal/stats/index.php

htdocs/commande/class/commandestats.class.php

htdocs/commande/stats/index.php

htdocs/compta/deplacement/class/deplacementstats.class.php

htdocs/compta/deplacement/stats/index.php

htdocs/compta/facture/class/facturestats.class.php

htdocs/compta/facture/stats/index.php