[ESS] Thanks for adding the ess-swv-* functions

[Douglas Bates]

My heartfelt thanks to whomever added the ess-swv-* functions to ESS -
you have saved me a great deal to time and energy.

As can be imagined, many of the Sweave documents that I write require
loading the Matrix and lme4 packages when running  Sweave on them and
it takes some time to load the lme4 package in a fresh R process.  The
first time that I ran

M-x ess-swv-weave

on one of my Sweave documents I thought I had done something wrong
because it completed so quickly.  It took me a while to realize that
ess-swv-weave used my existing ESS R process which already has the
Matrix and lme4 packages loaded.

It was a sort of "Well, duh!" moment for me as I though, "why didn't I
think of that?".  I'm very glad that someone else did think of using
the existing process.