bug#10181: split `diff-refine-change' in several faces

[Juri Linkov <juri@jurta.org>]

There is a related problem: currently vc-annotate uses dark background
even when the default background is light.  Would be nicer to have
another option similar to the existing `vc-annotate-background', that
will define the default foreground (instead of the default background) and
to put colors from color-map on the background instead of the foreground:

=== modified file 'lisp/vc/vc-annotate.el'
--- lisp/vc/vc-annotate.el	2014-02-10 01:34:22 +0000
+++ lisp/vc/vc-annotate.el	2014-06-18 08:55:39 +0000
@@ -109,6 +109,14 @@ (defcustom vc-annotate-background "black
   :type '(choice (const :tag "Default background" nil) (color))
   :group 'vc)
 
+(defcustom vc-annotate-foreground "black"
+  "Foreground color for \\[vc-annotate].
+Default color is used if nil.
+It it applied only when `vc-annotate-background' is nil."
+  :type '(choice (const :tag "Default foreground" nil) (color))
+  :version "24.4"
+  :group 'vc)
+
 (defcustom vc-annotate-menu-elements '(2 0.5 0.1 0.01)
   "Menu elements for the mode-specific menu of VC-Annotate mode.
 List of factors, used to expand/compress the time scale.  See `vc-annotate'."
@@ -347,7 +355,9 @@ (defun vc-annotate (file rev &optional d
 `vc-annotate-menu-elements' customizes the menu elements of the
 mode-specific menu.  `vc-annotate-color-map' and
 `vc-annotate-very-old-color' define the mapping of time to colors.
-`vc-annotate-background' specifies the background color."
+`vc-annotate-background' specifies the background color.
+`vc-annotate-foreground' specifies the foreground color
+when `vc-annotate-background' is nil."
   (interactive
    (save-current-buffer
      (vc-ensure-vc-buffer)
@@ -666,10 +676,15 @@ (defun vc-annotate-lines (limit)
                ;; Make the face if not done.
                (face (or (intern-soft face-name)
                          (let ((tmp-face (make-face (intern face-name))))
-                           (set-face-foreground tmp-face (cdr color))
-                           (when vc-annotate-background
-			     (set-face-background tmp-face
-						  vc-annotate-background))
+                           (cond
+                            (vc-annotate-background
+                             (set-face-foreground tmp-face (cdr color))
+                             (set-face-background tmp-face vc-annotate-background))
+                            (vc-annotate-foreground
+                             (set-face-foreground tmp-face vc-annotate-foreground)
+                             (set-face-background tmp-face (cdr color)))
+                            (t
+                             (set-face-foreground tmp-face (cdr color))))
                            tmp-face))))	; Return the face
           (put-text-property start end 'face face)))))
   ;; Pretend to font-lock there were no matches.