* bring closer to KNF
* when selecting a item in a menu, call the opt_action() callback with
a pointer to the struct menudesc, so the callback has a chance to find
out which item was selected. Having a seperate callback for each
item is ok for small menus, but not for ones with many objects.
* Add menu-option MC_NOSHORTCUT to not print letters ("a: ", ...)
in front of list items. Again, this is for menues with lots of entries
as e.g. the upcoming sysinst set_timezone() function composes.
* Fix a long-standing bug WRT pagewise scrolling - the cursor is now
properly placed one page up/down
(say width or height).
* work harder to make menu fit width-wise. (if necessary, move the menu
further left, and if that's not good enough exit with an error.)
* move menu system initialization out of process_menu() so that it can
be called earlier (e.g. by the sysinst main()), since it initializes
curses and other code might want to access the curses data structures
before process_menu() is invoked.
with that menu. The help screen is scrollable for long help screens.
The char '?' accesses the help screen as a menu command. Help screen text
is specified in the menu definition file with the menu.
