thanks for contributing!

You could create an AppleScript action and invoke an external utility 
like cscreen from there. 
There'll be more options with future releases. Right now, you can 
only access this functionality via the menu as configurable menu 
item. The plan is to make screen settings related actions available 
in a future release.

By default, you'll find all screen settings at

System > Screen Settings > [Your screen]

To use something in your own menu, be sure that your menu is actually 
the selected one in the Preferences (=> which basically means, you 
can see and browse it in the Preferences and its name is in the top 
of the tableview). If it is active, just selecting the respective 
item will trigger the action you're looking for.

Best regards, 
Felix