Fix a problem in TCutG::IsInside (thanks Otto Schaille). The original algorithm

from Rolf Nierhaus did not work correctly in case the Y value was equal
to the Y of one of the points and two consecutive points had the same Y value.


git-svn-id: http://root.cern.ch/svn/root/trunk@1088 27541ba8-7e3a-0410-8455-c3a389f83636