Add Change-Property Trait for Global Option Preferences

Add Change-Property Trait is a handy way to provide user access to Global Properties from the game.

Global Option Preferences provide what is effectively a Global Property limited to the current user’s scope. A Global Option preference value can be changed either via the Preferences panel or by using the Set Global Property trait.

Sometimes is convenient to provide access to some preference settings from a game window toolbar. However, the Global Option preferences does not provide an Add Change-Property trait.

A workaround is to use a GKC button to change the Global Option preferences via Set Global Property - but this requires a piece on the board to be used, which is a little more convoluted.

Request is to make the Add Change-Property trait available to Global Option preferences.