improve drracket's event log following code
improve drracket's event log following code

 - add support for getting a histogram of event timings

 - add support for scripting drr to be able to make comparisons

mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket