[ESS] Updated instructions/init file for XEmacs and Windows

[Rodney Sparapani]

>A couple of points:
>
>The Quickstart Package Guide at www.xemacs.org seems to suggest installing 
>under Program Files. Any reason why you chose to install in C:\XEmacs?
>
>The location of ess-site.el is hard-coded in your init.el. On unix, and 
>with my previous installation of ESS I could use just
>(require 'ess-site)
>rather than
>(load whatever)
>Likewise with Auctex I just have (require 'tex-site). The require format 
>seems preferable and means you don't have to update your init.el when 
>installing a new version (plus you don't have to change your website 
>document). Maybe a question for emacs gurus.
>
>David Scott
>  
>
Hi David:

The "Program Files" is a choice that I wasn't aware of, but it makes
sense since it is the default location for most Windows programs. 

As to your other point, load vs. require is a function of
the elisp variable load-path which is analogous to PATH.  An elisp file
in a directory that is in the load-path list can be loaded with require
without reference to the path to the file; otherwise, load is necessary.
I guess if "Program Files" had been used as the root, then these packages
would have been discovered automatically.  This is accomplished by the
function paths-construct-load-path, but apparently it is not working.
That may be because the inputs to the function are incorrect, check the
values of the following variables (likely only one of them will be set):
early-package-load-path, late-package-load-path, last-package-load-path.

By the way, I don't consider myself an emacs guru; I leave that to the 
wizards
at GNU and the XEmacs Project.

Rodney