Within core, `use self::` does not work to import these items.
And because core is not core_simd, neither does the existing `use`.
So, use this quirky hack instead, switching the import on a feature.
Now that we are thoroughly embedded in libcore, we don't need these on by default.
Indeed, their presence may provide confusing results during integration attempts.
Clean up references to the repo's previous name.
Removes the authors field, which is non-obligatory since RFC 3052.
Better to omit than confound: let git log be our witness.
