v3 performance tests improvements

[Tomi Ollila]

On Sat, Dec 15 2012, david at tethera.net wrote:

> This obsoletes the series 
>
>      id:1354762908-5788-1-git-send-email-david at tethera.net
>
> I addition to fixing some small things that Austin noticed, this
> series adds a convenience function "time_start" that unpacks the mail,
> prints the header, and recovers a database cache if present.  This
> should reduce the amount of boilerplate at the beginning of tests.

This patch set looks tolerable to me :-D

Tomi