Add more font selection options to Font2DTest

Font2DTest lets you select a Family + a style (plain/bold/italic/bolditalic)
But this doesn't let you select all the fonts
Families may report more fonts than this and you can't point to a specific font.

It would be useful to be able to select all fonts either by "full font name"
or by Family and then a menu that explicitly enumerates ALL fonts that report that same Family name.

I've previously hacked up things like this and then lost it.
So I'd like to check this in as part of the test.