Previously, we would pango_font_describe() every time the code ran and
we wouldn't ever hit the optimized quick exit.
The code now is a lot more complex because the
compute-actual-value-when-required-the-first-time approach is not
supported out of the box in GtkTreeModel (or GValue).
This subdirectory gets in the way when integrating the inspector
build more fully with GTK+, and does not really add anything.
Just move everything one level up.
