Pull over metrics code from ADAM about utils

[nfergu]

I have some updates to the metrics stuff to capture more granular timing stats from within Spark tasks. I won't be pushing anything for a few weeks though, so I can always push it here instead of to ADAM.

[fnothaft]

@nfergu ah, excellent! We're hoping that by moving some of the more general code out here, we'll make it more broadly accessible. Cheers to hearing that there will be updates coming soon!