Fixed comment for 'replace_colors' to remove ref to padding your color

array by one.  Also tell what happens if you pass too few colors.

lib/gruff/base.rb

@@ -253,10 +253,12 @@ def add_color(colorname)
       @colors << colorname
     end
 
-    # Replace the entire color list with a new array of colors. You need to
-    # have one more color than the number of datasets you intend to draw. Also
+    # Replace the entire color list with a new array of colors. Also 
     # aliased as the colors= setter method.
     #
+    # If you specify fewer colors than the number of datasets you intend 
+    # to draw, 'increment_color' will cycle through the array as needed. 
+    #
     # Note that (as with the 'theme' method), you should set up your color
     # list before you send your data (via the 'data' method).  Calls to the 
     # 'data' method made prior to this call will use whatever color scheme