icons may end outside of the map

while several cases have been fixed, it is still possible for icons to end up outside of the map area.

create a 100 px high map, add an icon. change icon to "server (128)", apply. change the icon to "rackmountable server 3d (128)", apply. icon is positioned outside the map area (in the db, y position is -30). it should also be verified that api has some sane validation for icon placement (negative placement might be allowed, but not if it's > than 50% of icon width height or such)

(you may use images from create/images/png directory to reproduce this problem)