bug#16177: 24.3.50; Display glyphs for hard spaces in color

[Drew Adams <drew.adams@oracle.com>]

FWIW -

http://www.emacswiki.org/emacs-en/download/highlight-chars.el

http://www.emacswiki.org/emacs/ShowWhiteSpace#toc2

From the Commentary, this description of what vanilla Emacs offers:

;; Vanilla Emacs can itself highlight hard spaces and hard hyphens,
;; and it does so whenever `nobreak-char-display' is non-nil, which it
;; is by default.  By "hard" space and hyphen I mean "no-break" or
;; non-breaking.  These are the non-ASCII Unicode characters with code
;; points 160 (#xa0) and 8209 (#x2011), respectively.
;;
;; This low-level vanilla Emacs highlighting does not use Font Lock
;; mode, and it cannot highlight only one of these characters and not
;; the other.
;;
;; See standard library `whitespace.el' for other ways to highlight
;; whitespace characters.  It does some things similar to what
;; `highlight-chars.el' does, plus other, unrelated things.  As its
;; name suggests, its effects are limited to whitespace characters.
;; It is also somewhat complicated to use (10 faces, 24 options!)...
;;
;; Besides being simpler, I think that `highlight-chars.el' has an
;; advantage of letting you easily highlight ONLY particular
;; whitespace characters.  `whitespace.el' apparently makes you pick
;; whether to highlight spaces and hard spaces together, or not, for
;; instance.