Debug|libdeng2|Widget: Forming the "path" name of a widget

If widgets are unnamed, use the address as a temporary name.
Client|MenuWidget: Menu items can be hidden and shown

Allows menus to be more dynamic in terms of what is displayed.
Client|Popup: Fixed a problem with preparing popups for opening

With a popup menu one must ensure that both the popup's and the
contained menu's layout is updated immediately after the popup is
shown.
Client|Task Bar: Items of the DE menu change depending on engine state

The Control Panel and unload items are only shown if a game is loaded.