*** A new format for menu items is supported.<BR>
In a keymap, a key binding that has the format
 (STRING . REAL-BINDING) or (STRING HELP-STRING . REAL-BINDING)
defines a menu item. Now a menu item definition may also be a list that
starts with the symbol `menu-item'.
<P>
The format is:
 (menu-item ITEM-NAME) or
 (menu-item ITEM-NAME REAL-BINDING . ITEM-PROPERTY-LIST)
where ITEM-NAME is an expression which evaluates to the menu item
string, and ITEM-PROPERTY-LIST has the form of a property list.
The supported properties include
<P>
:enable FORM      Evaluate FORM to determine whether the
		  item is enabled.
:visible FORM     Evaluate FORM to determine whether the
		  item should appear in the menu.
:filter FILTER-FN 
		  FILTER-FN is a function of one argument,
		  which will be REAL-BINDING.
		  It should return a binding to use instead.
:keys DESCRIPTION
		  DESCRIPTION is a string that describes an equivalent keyboard
                  binding for for REAL-BINDING.  DESCRIPTION is expanded with
                  `substitute-command-keys' before it is used.
:key-sequence KEY-SEQUENCE
		  KEY-SEQUENCE is a key-sequence for an equivalent
                  keyboard binding.
:key-sequence nil
	          This means that the command normally has no
		  keyboard equivalent.
:help HELP	  HELP is the extra help string (not currently used).
:button (TYPE . SELECTED)
		  TYPE is :toggle or :radio.
		  SELECTED is a form, to be evaluated, and its
		  value says whether this button is currently selected.
<P>
Buttons are at the moment only simulated by prefixes in the menu.
Eventually ordinary X-buttons may be supported.
<P>
(menu-item ITEM-NAME) defines unselectable item.
<P>