Menu:AddItem(cName,bAction,nHotKey,bPreBlock,bPostBlock):
  public: return true
  The current menu is appended with the next item, representing the action
  to be done when selecting this menu item.

  Parameter description:
  ~~~~~~~~~~~~~~~~~~~~~~
  cName: character: no default
   Menu item name

  bAction: code_block: no default
   The code block processed as the action when selecting this menu item.
   As parameter becomes the pointer to MD structure, which is the menu item
   stored in.

  nHotKey: numeric: no default
   It is InKey() key code, representing the "hot key" for this menu item.
   If not set the hot key is not created.

  bPreBlock: code_block: default je {||true}
   The code block, processed before entering this item.

  bPostBlock: code_block: default je {||true}
   The code block processed imediately after leaving the item.