A new package: xhmm. (#8620)
A new package: xhmm. (#8620)

* A new package: xhmm.

* Flake8.

* Support general BLAS.

mfherbst/spack,mfherbst/spack,iulian787/spack,matthiasdiener/spack,matthiasdiener/spack,iulian787/spack,krafczyk/spack,matthiasdiener/spack,mfherbst/spack,LLNL/spack,krafczyk/spack,LLNL/spack,matthiasdiener/spack,LLNL/spack,mfherbst/spack,LLNL/spack,iulian787/spack,LLNL/spack,krafczyk/spack,iulian787/spack,krafczyk/spack,krafczyk/spack,iulian787/spack,matthiasdiener/spack,mfherbst/spack