New command line parameter -i to refresh icons only

 * Icon lnk files added/removed from kdesk directories are immediately updated,
   No hooks are being called, thus reducing UI response time.
 * Unaffected icons are not redrawn, this removes the visual flickering effect.
 * The dump file is updated to account for the new icon counters.
Merge pull request #73 from KanoComputing/decouple-refresh-hooks

New command line parameter -i to refresh icons only