clearing a custom treeview model

[Charles Schmidt <cschmidt2 emich edu>]

I'm writing a custom GtkTreeModel for my application, and depending on
various user interactions would need to clear and repopulate the model
from a different data set at times.  What is the best way to clear the
model?  Just run gtk_tree_model_row_deleted() on all the rows (and if
so, how can I iterate through the GtkTreePaths without going too far?),
or is there a cleaner way to tell the view that the model is now empty?

-charlie