Fileman icon toolbar (#975)

* Add cut/copy/paste menu with icons
* Add icons, file limit to fileman

firmware/application/ui/ui_menu.hpp

@@ -83,6 +83,7 @@ public:
 	void add_item(MenuItem new_item);
 	void add_items(std::initializer_list<MenuItem> new_items);
 	void clear();
+	size_t item_count() const;
 	
 	MenuItemView* item_view(size_t index) const;