"color_t" structure to store color values (although currently it has all
the same fields that a GdkColor has; its currently advantage is that you
don't have to include any GTK/GDK stuff to declare it).
Add routines in the "gtk" directory to convert between "color_t" and
GdkColor values.
Define, in "prefs.h", all colors as "color_t" values rather than
GdkColor values. "prefs.h" now no longer needs to include <gtk/gtk.h>,
so don't include it.
svn path=/trunk/; revision=2692
Guy Harris