* gdesktop.c: Now desktop icons are stored in the layout_slots
array. We need to know which icons are in which slots.
(unselect_all): Use the layout_slots array.
(desktop_icon_info_place): Append the icon to the list in the
proper slot.
(desktop_icon_info_new): Initialize the position and slot fields
in the desktop icon info structure.
(desktop_icon_info_free): Remove the icon from its slot.
(desktop_destroy): Destroy the layout slots and the icons
properly.
(remove_from_slot): New convenience function to remove an icon
from the slot it is in.
(get_icon_snap_pos): Do a bit nicer snapping by really using the
closest slot.
Added a last_selected_icon variable to keep track of the icon that
was last selected, for shift+click selections.
(select_icon): Finish selection semantics and clean up. Now it is
nice and simple and complete.
(select_range): New function that handles range selections.
2f091b9509
