std.math API rework

[Ilya Yaroshenko via Digitalmars-d]

On Thursday, 6 October 2016 at 16:53:54 UTC, Ilya Yaroshenko 
wrote:
> Effective work with std.experimental.ndslice and and 
> mir.ndslice.array requires half of std.math be an exactly
>

EDIT: mir.ndslice.algorithm