r-sig-mixed-models now indexed in finzi.psych.upenn.edu

I've added the complete archives of this mailing list to the index in
my search site: http://finzi.psych.upenn.edu/search.html

This is the same site as RSiteSearch, so "R-sig-mixed-models" might
work as an option in that function.

It is not in the default search path.  You have to check the box (or
choose the option in RSiteSearch).

Jon