Editing will be done simply by creating first .desktop file and letting ede-desktop to read it, performing some
checks to determin if only content was changed or file was renamed. Using this scheme, beside it simplify the code,
it addresses the cases when icon was modified outside the desktop or removed.
These things could be solved by using DirWatch, but I'm trying to rely less on OS notification system...
By default, 'empty' icon should be used. It is now shown in preview box and will
be selected when icon wasn't explicitly chosen. Also, redraw full desktop when icon was removed, to
prevent displaying icon which isn't available.
Added small delay when icon was removed so directory watcher skip remove event.