Fixed crucial issue of hovering not working

Hovering was closing almost immediately. Problem was reversed logic in
checking the coordinates. Was actually checking if the mouse was inside
of the grace area instead of outside of it.
Hovering now working correctly

Displays the properly sized image in the centre of the window. Moving
from link to link seems to be working as expected. Also cleaned up the
debugging output (the excessively verbose mouse positions aren't output).