as, on a large capture, it could take a significant amount of time.
Let the user stop the computation and, if they do, don't pop up the
statistics dialog box.
Create a new header file declaring the routines to create, update, and
destroy progress dialog boxes; those routines' APIs don't depend on
GTK+, but others declared in "ui_util.h" do, and we don't want to oblige
a source file to depend on GTK+ headers unless it uses a GTK+ API or an
API that depends on GTK+.
svn path=/trunk/; revision=3179
Guy Harris