* New: In cumulus.designflow: add yosysnp to manage Yosys without
Python support enabled.
Add klayout support for running scripts in batch mode.
Add generic system command support.
* Change: In cumulus.designflow.task.TaskFlow, systematically
convert pathes (str) into pathlib.Path in targets and depends.
* New: In cumulus.designflow.clean.Clean, add cleaning by glob.