- gimp_rgb_list_names() ported as gimp_color_list_names() using NUL-terminated
  GimpColorArray.
- GimpColorHexEntry uses the new function (and is therefore now GimpRGB free!).
- gimp_rgb_parse_name() deleted as it's unused since my previous commit.

With all this, gimprgb-parse.c is now deleted from the repository! \o/