fixed a bug with the graph operator

Signed-off-by: Sébastien Boisvert <sebastien.boisvert.3@ulaval.ca>
added detection of screen geometry

Signed-off-by: Sébastien Boisvert <sebastien.boisvert.3@ulaval.ca>
moved the inventory on the left

Signed-off-by: Sébastien Boisvert <sebastien.boisvert.3@ulaval.ca>