stuartmcalpine

Results 2 issues of stuartmcalpine

When `Write_group_array_file=1` the function `MPICollectFOF` is called, which uses `mpi_indexlist` in the file `mpiroutines.cxx` which I think has become redundant? (it's no longer initialised in `tipsyio.cxx`). I get a segfault...

**Added a github actions workflow (nersc-ci.yml):** This triggers the NERSC CI pipeline. At the moment this is just triggered manually, however you can change this to on push, schedule, etc....