The GTK colour selector does not provide full 8-bit resolution in

The GTK colour selector does not provide full 8-bit resolution in
the RGB values (it deals in floats with 2 d.p. instead). Hence I've
replaced the static RGB text item in the Colours panel with three
little edit boxes, so that a user can type in exact 0-255 RGB values
if necessary. This should have the additional advantage of being
quicker than faffing with the colour selector if you already know
exactly what you want and are in a hurry!

[originally from svn r2978]