GtkSpinButton proposal

[Mark Crichton <crichton expert cc purdue edu>]

Hello,

While going through some of the early keg tracker sources, I noticed that
their spinbutton widget was exactly the same as the one in gtk, with one
change....the sprintf's in the code were replaced such that they printed
hex and not decimals.

I thought this was rather bloatful, so I started looking at ways to make
gtkspinbutton be a bit more flexible.  The best way I can come up with is
to create a custom callback in the widget that points to your own sprintf
routine.

Any comments?  (I can have this thing coded in about 15 minutes)

Mark