Add an example of a member of type char* in class Event (see fEventName)

Add the keywork "EXEC" in the comment field of the member fLastTrack
to test the automatic action on demand to be introduced in TRef,TRefArray.


git-svn-id: http://root.cern.ch/svn/root/trunk@3280 27541ba8-7e3a-0410-8455-c3a389f83636