git-svn-id: http://root.cern.ch/svn/root/trunk@34141 27541ba8-7e3a-0410-8455-c3a389f83636

 add vavilov functions: a fast and an accurate implementations

 fast implementation is based on  G115 from the Cernlib VAVDEN 
 while the accurate one is based on G116 (VVIDEN)

more info and motivation is provided in 
http://root.cern.ch/phpBB3//viewtopic.php?f=15&t=10299

add also classes Cdf, Pdf and Quantile implementing the ROOT::Math::IParamFunctionOneDim interface

add a testProgram with a test class


git-svn-id: http://root.cern.ch/svn/root/trunk@34123 27541ba8-7e3a-0410-8455-c3a389f83636