Re: GTKTreeView navigation improvement

[Andrey M <admartch gmail com>]

> If someone makes changes that breaks your new feature, there should be
> regression tests that detects this. To run tests you do 'make check'.
I don't know how to do that (or if it even applies to this).

Additionally, as long as the functionality of the following remains
the same (as of GTK+2.18), the patch should always work.
{GtkRBNode::children == NULL} when GtkRBNode is either collapsed or
has no children.
{gtk_tree_path_up(GtkTreePath *path)} moves the innerworkings of path
to the parent.
{gtk_tree_view_set_cursor(GtkRBTree *tree, GtkTreePath *cursor_path, NULL,NULL)}

-Andrey