Renamed custom lisp file directories.

The latest verions of GNU emacs have made .emacs.d/ the default
directory for user lisp customizations.  I converted my .elisp/
directory to the new standard for consistancy.  I also converted my
somewhat confusingly named site-lisp/ directory to a packages/
directory to distinguish it from the actual site-lisp/ directory used
by emacs for system wide lisp packages.  This change required updating
both documentation and paths in elisp files.
Removed Custom section from .emacs file.

I don't use the Custom feature of emacs any more.  I find its
interface terrible and prefer to manually set things in my .emacs.d/
files.  I still kept a few things as Custom set because I hadn't yet
figured out how to set them manually.  I've determined that I don't
even need most of the options anymore.  Emacs has changed its defaults
over the years (not surprising given that my .emacs file is almost 10
years old).  The only thing I still need is the save-place
functionality -- which I added to my variables.el file.
Replaced repeated paths in .emacs with constants.

When changing the name of my elisp directory, I got annoyed with all
the places I had to replace the paths to files via query-replace
whatever.  I replaced the long paths with "constants".  Strangely,
this worked out to be actually more code in this circumstance, but if
I ever mess around with my directory structure again I'll be glad I
did this.
Corrected typos.