[PATCH libXcomposite] COPYING: add missing copyright notices

[Alan Coopersmith]

Thanks - pushed all 3 (libXt, libXcomposite, libXfixes) along with the
updates of the Sun licenses to the new X.Org standard format.

-- 
	-Alan Coopersmith-           alan.coopersmith at sun.com
	 Sun Microsystems, Inc. - X Window System Engineering