functions by an explicit loop to take into account the case of the same
object (with different drawing options) being added to the same list.
This, in principle, should be covered by the "slow" option in TList::Delete,
but the logic does not work. To be revesited!


git-svn-id: http://root.cern.ch/svn/root/trunk@7920 27541ba8-7e3a-0410-8455-c3a389f83636