libs/utils/trace: add support for normalize_time
libs/utils/trace: add support for normalize_time

Pass normalize_time down to trappy.  Sometimes it's useful to have the
same time between kernelshark and trappy.  Trappy supports this with
normalize_time but the Trace class doesn't allow you to specify it.  Let
Trace accept this parameter and pass it down to trappy.

close #57

bjackman/lisa,credp/lisa,JaviMerino/lisa,joelagnel/lisa,ARM-software/lisa,mdigiorgio/lisa,ARM-software/lisa,arnoldlu/lisa,ARM-software/lisa,credp/lisa,credp/lisa,mdigiorgio/lisa,joelagnel/lisa,credp/lisa,bjackman/lisa,arnoldlu/lisa,ARM-software/lisa