[FR] add getProperties() to PopupMenu, like the one in Component

Most of the menus I have are all drawn with the same LookAndFeel.

For some of them, I’d like to customize some minor appearance detail, that doesn’t justify the creation of a new LookAndFeel just for that.

For regular Components, I already do that by adding some information to the Component properties, querying it in the LookAndFeel. It would be very nice if the same could be done with PopupMenus.

I believe the change would be very simple: add a NamedValueSet member variable to PopupMenu, and make it accessible with the getProperties() member function, exactly as it happens in Component.

What does the JUCE team think about it?