Add TBDebugTimeStamp and TBDebugTimeStampsOn, copied from tbsetup/libtestbed.pm.in which we use on boss. I have modified these routines in two ways (which need to be merged back into original version at some point).
Add TBDebugTimeStamp and TBDebugTimeStampsOn, copied from
tbsetup/libtestbed.pm.in which we use on boss. I have modified these
routines in two ways (which need to be merged back into original
version at some point).

* import/require Time::HiRes module (/usr/ports/devel/p5-Time-HiRes)
  to get higher resolution gettimeofday() function that reports
  microseconds and seconds. Change the output routine to append the
  microseconds to the original HH:MM:SS timestamps that get printed.

* When turning timestamps on dynamically with TBDebugTimeStampsOn(),
  set an environment variable, and read that in so children also know
  to turn them on.

nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome