std.benchmark ready for review. Manager sought after

[Martin Nowak]

> I've analyzed this quite a bit at work and the average and median are  
> not very informative. You need the mode, but in most benchmarks the mode  
> is very close to the minimum, so using the minimum is even better.
>
How is it better?

> In speed measurements, all noise is additive (there's no noise that may  
> make a benchmark appear to run faster). There are also quite a few  
> outliers. Recording the average will include a fair amount of noise.
>
The benchmarked function itself could have a relevant variance, e.g.
when using randomized algorithms. You already get that from the LRU table
in the array append cache.