Add support for Duet Display screen names

From Reliable way of identifying multiple display

When using Duet Display with vuo.screen nodes, the Duet screen can’t be selected/identified by name because the Duet driver doesn’t populate the standard field for display name (DisplayProductName = { "en_US" = ""; }).

Vuo could work around this by looking at a different field (IODisplayLocation) to detect if Duet Display is being used.

This is very quick, so chosen to be implemented.

In Vuo 1.2.5 we added support for Duet Display screen names. And for some related apps that weren’t providing the standard information: Splashtop XDisplay, GoodDual Display, Yam Display.