- 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
* Adds catch, cppunit, spdlog, tinyxml(1 and 2), google benchmark
Tinyxml comes in two flavors, 1 and 2. Each comes in several
versions... So they cannot be easily united into a single package.
* Use CMakePackage and friends, add copyright
Also eleminate debug/release variants, since it no longuer fits in the
CMakePackage format.
* Remove unnecessary url
* spdlog now has tagged releases
* Remove unnecessary url argument
* Fewer quotes in cmake args, because magic
* Incorrect base class for tinyxml
