Hi,
The goal of this PR is to:

Introduce command to share with menu, toolbar, button and checkbox

• Plan minimum: just use one command to initialize items in:
  • menu,
  • toolbar,
  • button and
  • checkbox
• plan maximum: share state: selected, pushed, checked, etc. with (drawer read from here?):
  • menu,
  • toolbar,
  • button and
  • checkbox

please, compare: widget_show2 manual item creation
with: widget_show2 created with command

This is my first version, and you will need to review and redesign a few thing in it, but I hope this is the first draft of what we wanted. Maybe the correct way is to create a command "interface" to add to any of the supported classes?

First just I will try to compare/document the possible affected parts:

• menu vs. toolbar:
  toolbar is a widget, menu - not.
  • menu: hold a plain ptr to an implement which use structures in a drawerbase::menu namespace.
    The later includes a menu_type, menu_item_type, and the enum checks,

			enum class checks
			{
				none,
				option,
				highlight
			};

menu_item_type hold a plain pointer to a menu_type and all the state-data of the item which can be acceded with an item_proxy which hold a pointer to the menu and the position order of the item.
A new item can be added with menu::append or menu::insert.

			enum class tools
			{
				separator,
				button,
				toggle,
				dropdown
			};

• toolbar: the drawer hold a plain pointer to a drawer_impl_type that hold an item_container of toolbar_items. The later hold the state-data.
  A new item can be added with toolbar::append or with item_proxy::dropdown_append.

• button: is a widget_object class, which hold a DrawerTrigger, a shared Events and an scheme_type scheme_. The state-data is hold deeper in the windows structure (like the caption), and in these members. The DrawerTrigger holds a unique_ptr<impl> that have attributes where the state-data image, focused, pushed, etc are.

• checkbox: is a widget_object class, which hold a DrawerTrigger, a shared Events and an scheme_type scheme_. The state-data is hold deeper in the windows structure (like the caption), and in these members. The DrawerTrigger holds a unique_ptr<implement> that have element::crook_interface::data data_; where the state-data check_state { unchecked, checked, partial }, radio, etc are.

• Implement/use checks/tools

• create command: a no-widget class, wich state-data useful to set and to share menu, toolbar, button and checkbox

  • title/text, tooltip/status
  • event handler
  • image (a shared type),
  • set/get image
  • checks style
  • flags: enabled, checked

• Make menu and toolbar API similar:

  • prefer item_proxy

• In menu:

• menu::append(shared_command)
• menu::insert(shared_command) .
• in menu_type
• in menu_item_type <---- real data here (generalize?)
  • hold a shared_command
  • add constructor that take a shared_command
  • set/get shared_command (to be used by other constructors)
  • really need 'linked'?
• add to item_proxy
  • set/get shared_command (to be used by other constructors)
  • set/get image
  • answerer()
• reuse renderer_interface?

• In toolbar:

• in toolbar_item <---- real data here
  • hold a shared_command
  • in constructor that take a type, text, image and event
    • create a shared_command
  • add constructor that take a shared_command
  • set/get shared_command (to be used by other constructors)
• in dropdown_item <---- real data here
  • hold a shared_command
  • in constructor that take a type, text, image and event
    • create a shared_command
  • add constructor that take a shared_command
  • set/get shared_command (to be used by other constructors)
• add item_proxy& dropdown_append(shared_command command);
• add item_proxy append(tools t, shared_command command);
• add void insert(size_type pos, tools type, shared_command command)
  • return item_proxy
• add void push_back(tools type, shared_command command)
  • return item_proxy
• dropdown_item construct take a menu and vice ferse?

• In button:

• hold a shared_command
• add constructor that take a type, text, image and event
  • create a shared_command
• add constructor that take a shared_command
• set/get shared_command (to be used by other constructors)

• In checkbox:

• hold a shared_command
• add constructor that take a shared_command
• set/get shared_command (to be used by other constructors)