UTF8 + SIMD = win

[bearophile]

Walter Bright:

> SIMD isn't going to speed things up at all for decoding one 
> character. It is for transcoding a large array.

Right.
Maybe you remember my two or three posts about vectorized 
lazynesss and related matters (that later was a bit implemented 
in the half-eager map of std.parallelism). Introducing some 
vectorized lazyness in std.algorithm when the iterable is a UTF-8 
(or rarely UTF-16) string allows to use SIMD and probably leads 
to higher performance.

Bye,
bearophile