(format_file): remove unused arguments.

Signed-off-by: Andrew Borodin <aborodin@vmail.ru>
(sel_skin_button): simplify.

Signed-off-by: Andrew Borodin <aborodin@vmail.ru>
src/filemanager/boxes.c: move statuc functions to the matched section.

Signed-off-by: Andrew Borodin <aborodin@vmail.ru>