Modify TPolyLine::DistancetoPrimitive to support the case of a filled and closed

polyline. In this case the object is picked when the mouse is inside
the polygone, otherwise the object is picked only when the mouse is closed
to one of lines of the polyline.


git-svn-id: http://root.cern.ch/svn/root/trunk@7510 27541ba8-7e3a-0410-8455-c3a389f83636