OpenMP GPU support, efficiency updates, streamlined make
OpenMP GPU offload, tested with CCE 11.0.0. Longwave Jacobians aren't computed if the optional arguments aren't provided. Finalization methods for optical properties arrays are introduced. Make is streamlined to use environment variables and omit config files. Small changes for efficiency and robustness. Continuous integration is evolved; includes gfortran 9 and 10 on Github actions; current Nvidia and Intel HPC compilers in containers; Cray CPU and OpenMP GPU and PGI 20 OpenACC.