- remove the old LGPL license headers from all files in Spack
- add SPDX headers to all files
- core and most packages are (Apache-2.0 OR MIT)
- a very small number of remaining packages are LGPL-2.1-only
* cosmomc: New package CosmoMC
* cosmomc: Improve version numbering scheme
* planck-likelihood: New package
* cosmomc: Pacify flake8
* cosmomc: Code cleanup as requested in the review
* cosmomc: Various updates suggested during review
* cosmomc: Limit compiler versions (as documented in the build instructions)
* cosmomc: Correct flake8 error
* cosmomc: Use `libs` instead of `lapack_libs`
* planck-likelihood: Make makefile output more verbose and readable
* planck-likelilhood: Correct order of libraries when calling linker
* cosmomc: Clean up check for suitable compiler
* planck-likelihood: Use modern mechanism to set environment variables