Add one pixel to the bin width and height when drawing TH2 with the COLZ option
Add one pixel to the bin width and height when drawing TH2 with the COLZ option

This prevent having sort of "grid" effect due to space between bins when drawing TH2 with the COLZ option

Signed-off-by: Fons Rademakers <1ec492889ec4314e6ce1fb58ec289eb0358186c9@cern.ch>

tc3t/qoot,tc3t/qoot,tc3t/qoot,tc3t/qoot,tc3t/qoot,tc3t/qoot,tc3t/qoot,tc3t/qoot,tc3t/qoot,tc3t/qoot