There should be documentation for the McLachlan arrangement. There is currently documentation at https://bitbucket.org/einsteintoolkit/mclachlan/raw/8f8946917e842666ecc49ec798c2906a01a27527/doc/mclachlan.tex) but this is mostly installation instructions, which is not relevant for most users of the ET. This documentation is not built as part of the normal documentation build process.
- Add standard Cactus arrangement documentation;
- Transfer relevant information from mclachlan.tex;
- We should probably follow the usual thorn documentation template for this arrangement documentation, simultaneously describing all the thorns. We should explain precisely what formulation is evolved (possibly by reference to the .m file, but it would be nice for users not to have to browse through source code).