raspberry pi cluster case

# openscad-raspberrypi-casecustomizable cases for raspberry pibuild with build-all.sh```bash$> ./build-all.shrpi-case-bottom-cluster-1rpi-case-bottom-cluster-2rpi-case-bottom-cluster-3rpi-case-bottom-cluster-4rpi-case-bottom-no-cluster-1rpi-case-bottom-no-cluster-2rpi-case-bottom-no-cluster-3rpi-case-bottom-no-cluster-4rpi-case-top-cluster-with-aerationrpi-case-top-cluster-without-aerationrpi-case-top-no-cluster-with-aerationrpi-case-top-no-cluster-without-aeration```