fix bug https://savannah.cern.ch/bugs/?87251 in TMath::Quantiles
fix bug https://savannah.cern.ch/bugs/?87251 in TMath::Quantiles

 - reimplement the method following R impelmentation. This fixes also the case for type =3, 
 where a different result was returned


git-svn-id: acec3fd5b7ea1eb9e79d6329d318e8118ee2e14f@41830 27541ba8-7e3a-0410-8455-c3a389f83636

bbockelm/root-historical,bbockelm/root-historical,bbockelm/root-historical,bbockelm/root-historical,bbockelm/root-historical,bbockelm/root-historical,bbockelm/root-historical