Merge changes made in Emacs trunk.

Merge changes made in Emacs trunk.

2011-02-21  Chong Yidong  <cyd@stupidchicken.com>
 * color.el (color-name-to-rgb): Rename from color-rgb->normalize.
 Autoload.  Add optional arg FRAME, and pass it to color-values.
 (color-complement): Caller changed.  Doc fix.
 (color-gradient): Rewrite for better clarity and efficiency.

2011-02-20  Chong Yidong  <cyd@stupidchicken.com>
 * shr-color.el (shr-color->hexadecimal): Use renamed function names
 color-rgb-to-hex, color-name-to-rgb, color-srgb-to-lab, and
 color-lab-to-srgb.

2011-02-20  Drew Adams  <drew.adams@oracle.com>
 * color.el: First part of merge from hexrgb.el.
 (color-rgb-to-hex): Rename from color-rgb->hex.
 (color-rgb-to-hsv): Rename from color-rgb->hsv.  Force hue and
 saturation to zero if the value is too small.
 (color-rgb-to-hsl): Rename from color-rgb->hsl.
 (color-srgb-to-xyz): Rename from color-srgb->xyz.  Doc fix.
 (color-xyz-to-srgb): Rename from color-xyz->srgb.  Doc fix.
 (color-xyz-to-lab): Rename from color-xyz->lab.  Doc fix.
 (color-lab-to-xyz): Rename from color-lab->xyz.  Doc fix.
 (color-lab-to-srgb): Rename from color-lab->srgb.  Doc fix.
 (color-cie-de2000): Doc fix.