Remove the deprecated fehler module from color; adjust gray values

(from dev 3b91484c1049)

README.md

@@ -41,7 +41,7 @@ are regenerated on each release — patches cannot be merged directly.
 Report problems (or send patches) to the author; accepted changes are
 applied to the development tree and appear in a following snapshot.
 
-This snapshot was assembled from development commit `a910e11431d2`.
+This snapshot was assembled from development commit `3b91484c1049`.
 
 ## License