-- Command: menu ID/K, ATTRS/K/M, LABEL/K/F
     This command begins the definition of a menu. Menus are defined by
     placement of other menus and menu items between a `menu' and
     `endmenu' pair.  If a menu is defined within a window definition
     (i.e. between a WINDOW and ENDWINDOW pair), but outside any group
     definitions then the menu will be added to the window menu strip. 
     If a menu is defined within a group then a context sensitive menu
     will be created for the group (i.e. when the mouse pointer is over
     the group and the right mouse button is pressed then a popup menu
     will be displayed). Note that only one menu may be defined for a
     context sensitive menu (all others will be ignored).

        * ID [I..] - an id can be assigned to a menu for later
          reference. The id can be any combination of up to 5
          characters.

        * LABEL [I..] - the menu must be given a label which will be
          displayed in the menu bar of the window.

        * ATTRS [ISG] - with this option any MUIA attribute TAGs may be
          set or retrieved (see Attribute TAGs).

     Some useful TAGs for use with the menu command are:

          TAG_Name =                        TAG_id          Flags Type
          
          Menu_Enabled =                    0x8042ed48 /* V8  isg BOOL */
          
          Note: Consult MUI:Developer/Autodocs/MUI_Menu.doc, MUI_Area.doc and
                MUI:Developer/C/Include/libraries/mui.h