From Andrei Gheata

- TGeoPgon::DistToIn() - new algorithm 50-200% faster than the old one
(depending on the number of edges) fixing the existing pgon problems
- TGeoPgon::ComputeNormal() - corrected a wrong sign
- TGeoManager::Safety() corrected in case of MANY geometries
- Bug fix raytracing + a minor fix in the calling sequence (now there is
a similar behavior of TGeoVolume:Raytrace/Draw)


git-svn-id: http://root.cern.ch/svn/root/trunk@7569 27541ba8-7e3a-0410-8455-c3a389f83636