Now you can hook activation via GAbstractView::on_activation.
The design still isn't quite right, we should eventually move the selection
away from the model somehow.
Replace the custom DirectoryView widget with a GTableView subclass.
This was pleasantly straightforward and it's so cool seeing the huge
increase in app quality from GTableView. :^)
My needs are really quite simple, so I'm just going to add what I need
as I go along. The first thing I needed was a simple box layout with
widgets being able to say whether they prefer fixed or fill for both
their vertical and horizontal sizes.
I also made a simple GStatusBar so FileManager can show how many bytes
worth of files are in the current directory.
