RE: Info about color-values need be revised

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

> In ELISP manual, info about color-values is not true any more with NS
> port merged. It says return value is (R G B).
> 
> In NS port, color-values uses function xw-color-values:
> The return value is (R G B Alpha).

Ouch! Why is that? Why does a platform-specific function change the meaning of a
generic function that way? And why should the generic function's signature be
changed accordingly (breaking existing code)?

Code that uses `color-values' depends on its return value being a 3-element
list. That includes any NS code that uses `color-values' (as opposed to
`xw-color-values'). Seems like any NS code that needs the Alpha info should call
`xw-color-values' directly (or some other NS-specific function) - and
`color-values' should be left alone.