[Bio-packaging] testing out guix

[Ricardo Wurmus]

> Since we are adding packages to GNU Guix at such a rapid rate, I
> propose we announce them here too when they go in.

I agree!

> and Ricardo added the following Python packages:
>
>   python-scikit-learn: Update to 0.16.1.
>   python-scikit-learn: Use OpenBLAS instead of ATLAS.
>   python-scipy: Build with OpenBLAS and lapack.
>   python-numpy-bootstrap: Add lapack to inputs.
>   python-numpy: Build against OpenBLAS.

They have been in Guix for a while now.  I only updated sklearn and
replaced ATLAS with OpenBLAS, so that the packages (and any packages
that depend on them) can be substituted.  Previously, I always had to
download all inputs for numpy to build the dependency graph rooted at
numpy whenever one of the inputs had changed.  Now binary substitutes
are available for these packages.

~~ Ricardo