fixed position center on modal

Signed-off-by: filipe garcia <filipe.c.garcia@gmail.com>
updated jQuery to version 1.9.1

Signed-off-by: filipe garcia <filipe.c.garcia@gmail.com>
working in firefox also

I was using document.height and that was not supported in firefox

Signed-off-by: filipe garcia <filipe.c.garcia@gmail.com>