Add Josef Leydold for his contribution to UNURAN.

git-svn-id: http://root.cern.ch/svn/root/trunk@18333 27541ba8-7e3a-0410-8455-c3a389f83636

README/CREDITS

@@ -365,6 +365,10 @@ N: Wim Lavrijsen
 E: WLavrijsen@lbl.gov
 D: PyRoot package
 
+N: Josef Leydold
+E: leydold@statmath.wu-wien.ac.at
+D: UNURAN package and interfaces
+
 N: Sergey Linev
 E: S.Linev@gsi.de
 D: XML interface package