rgb number scheme

[John Taber <jtaber johntaber net>]

gtkmm uses the gdk color  r_g_b numbering scheme that goes from 0-65535 
instead of the more normal 0-255.  Can anyone explain what the 65535 is based 
on.   I'm guess we have to divide all our color numbers and use 
set_rgb_p(...) - I'm wondering why there isn't a set_rgb method for using the 
normal 0-255 range.