Add over-big test case for preview (much of size from a modified copy of

Add over-big test case for preview (much of size from a modified copy of

Wed Jul 23 17:52:01 2003  Owen Taylor  <otaylor@redhat.com>

        * testfilechooser.c: Add over-big test case for preview
        (much of size from a modified copy of
        gdk_pixbuf_new_from_file_at_size())

        * gtkfilechooserutils.[ch] gtkfilechooser.c
        gtkfilechooserprivate.h gtkfilechooserimpldefault.c:
        Add get_preview_path() as a virtual function; implement
        update-preview signal that was in the header file.

        * gtkfilechooserimpldefault.c: Finish a simple preview
        widget implementation.