New method of widget ID assignment:
now widget ID is a value of unsigned long type. Dlg_head structure now has
new filed widget_id that contains a ID of the next added widget. When new
widget is added into dialog, widget_id is set as ID of it and then
incremented.
Signed-off-by: Andrew Borodin <aborodin@vmail.ru>
menubar_set_visible(): new function to get rid of menubar_visible global variable
in widgtes library.
menu_set_name(): new function to avoid total recreation of main menu
after change panel layout.
Signed-off-by: Andrew Borodin <aborodin@vmail.ru>