further optimize window smart placement by reducing obstacle calcs
further optimize window smart placement by reducing obstacle calcs

previously the obstacle list would build from the bottom up, skipping
fullscreen and maximized windows. this would lead to cases where windows
would be moved to avoid windows which were fully obscured, and also cases
where unnecessarily large amounts of looping would occur related to the
existence of maximized windows

tasn/enlightenment,tasn/enlightenment,rvandegrift/e,tasn/enlightenment,rvandegrift/e,rvandegrift/e