My thought was to parallel ```Figure.delaxes```, but adding a ```Colorbar.remove``` would work as well.  Alternatively, I could keep ```Figure.delcolorbar``` but move most of the code to a new ```Colorbar,remove_gridspec`` function.  That way, the only implementation present in the Figure class would be the ```delaxes``` call and the ```remove_gridspec``` call.

@pelson and @tacaswell, am I right in assuming that you'd both prefer a ```Colorbar.remove``` function?  If so, I'll change to that.