Commit 49a1762 added many directories to the `Directories` field as
well as corresponding directory entries for most, but not all, of the
new entries.
The missing entries manifest as Gtk warnings when doing some operations
via command line, e.g. opening an image using `open`.
```
$ open rainbow-0.png
(eog:248786): Gtk-WARNING **: 15:18:32.794: Theme directory scalable/emotes of theme Cosmic has no size field
(eog:248786): Gtk-WARNING **: 15:18:32.794: Theme directory scalable/legacy of theme Cosmic has no size field
(eog:248786): Gtk-WARNING **: 15:18:32.794: Theme directory scalable/ui of theme Cosmic has no size field
(eog:248786): Gtk-WARNING **: 15:18:32.794: Theme directory scalable-up-to-32/status of theme Cosmic has no size field
```
Add directory entries for the missing sections.
Fixes#36
during icon lookup, it uses the first index.theme it finds, (I assume only when the eventually chosen theme with the icon doesn't have an index.theme?) we should include all the standard directories in our theme even if we don't use them.
