adding color to figure

[John W. Eaton]

On  7-Dec-2007, Shai Ayal wrote:

| The following patch adds the color property to figures, I leave the
| gnuplot implementation to someone more suitable than me. I will
| implement it in the "new" backend.
| 
| Shai
| 
| 2007-12-07  Shai Ayal  <shaiay at users.sourceforge.net>
| 
|         * graphics.h.in (class figure) add the color property
|         graphics.cc (class figure) ditto

I checked in this change.

Thanks,

jwe