add new methods GetBuiltDate() and GetBuiltTime(). The existing methods

GetVersionDate() and GetVersionTime() report now the date/time the version
was created (i.e. when "make version" is run).


git-svn-id: http://root.cern.ch/svn/root/trunk@11962 27541ba8-7e3a-0410-8455-c3a389f83636