add SetX,Y as suggested by A. Vargas (see roottalk)


git-svn-id: https://root.cern.ch/svn/root/trunk@48477 27541ba8-7e3a-0410-8455-c3a389f83636
tiny mod


git-svn-id: https://root.cern.ch/svn/root/trunk@48478 27541ba8-7e3a-0410-8455-c3a389f83636