This was requested on IRC; the docker image in the registry is updated already.

The complexity with model items vs row items is really confusing. Add to
that treelistmodel position vs child model position vs parent position,
and you're so confused, even the best naming can't help.

And once you're there, consider passthrough vs non-passthrough...

Fixes #1341

This reverts commit 03679d43.

listlistmodel is private

When passthrough is enabled, it should return the GType
of the child GListModels; when disabled, it should be
GTK_TYPE_TREE_LIST_ROW.

The conditions are inverted however, causing a few
warnings to trigger.

Fix that by returning the correct GType.

treelistmodel: Fix memory leak

See merge request !344

gtk_tree_list_model_init_node() increases the reference count
of the model passed. Let's not do that, and let it take the
model passed.

treelistmodel: Fix signal emission on row destroy

See merge request !343

toolbar: Use hexpand/vexpand Gtk+ properties

See merge request !334

Clarify some wording.

We were adding items in reverse order, oops.

gdkselectioninputstream-x11: Fix memory leak

See merge request !340

Now we show all the controllers that are relevant when widget gets sent
events.

Now display how many items were filtered (if any) and how many
directories remain to be sanned (if any).

Add a simple search that does a case insensitive substring search of the
file paths.

This is way more complicated than it should be, because it requires
manually limiting the number of open file enumerators.

On the other hand, it exhaustively tests the items-changed emission of
all involved listmodels because those signals come in pretty much
randomly.

It's also 50% slower than the sync version, with the caeat that the sync
version only shows the UI after it's done loading, while this version
shows it right away.

... and make the lists long by autoexpanding the tree.

And rename GtkInspectorGestures => GtkInspectorControllers, too.

This requires removing support for gesture groups.

This model just takes an object and a property name and recursively
looks it up. In particular, I want it for:

widget, widget.parent, widget.parent.parent, ...

The code gets rid of the GtkTreeView and replaces it with a GtkListBox.

Most of the logic is now done via GListModel subclasses.

A big change is that this new list is now tracking updates itself and
doesn't need to be manually updated. All code that used to cause rescans
or add forgotten objects to the tree has been removed.

If objects are missing from the object tree, the logic for tracking them
needs to be added.

Fixes CI.

Instead of the outdated render node view, use modern GTK APIs.

It used to be a treeview.