[gtkmm] Emergency: unwrapped GtkTreeModel API

[Daniel Elstner <daniel elstner gmx net>]

Hi,

gtk_tree_model_row_changed()
gtk_tree_model_row_inserted()
gtk_tree_model_row_has_child_toggled()
gtk_tree_model_row_deleted()
gtk_tree_model_rows_reordered()

are not wrapped in gtkmm-1.3.26.  Most of these functions are only of
interest when implementing a custom TreeModel, but row_changed() seems
to be really necessary.

The scenario is as follows:  If you install a custom cell data function
to display data that's not directly stored in the model, you've to send
out notification of model changes manually.  Without a row_changed()
method you'd have to work around it:

a) self-assignment:
   const FileInfoPtr fileinfo = (*iter)[columns.fileinfo];
   (*iter)[columns.fileinfo] = fileinfo;

b) plain C:
   gtk_tree_model_row_changed(model->gobj(), path.gobj(), iter.gobj());

I ran into this problem in my app regexxer, where I want to paint the
list row of a modified file red.  To do this I've a cell_data_func()
callback that accesses buffer->get_modified().  To force redrawing of
the TreeView, I need to send out notification in the
signal_modified_changed() handler.

Murray, do you think an API addition would be justified?  It wouldn't
even break the ABI.

--Daniel