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2019-06-12
* Add action as CLI optional argument. The action has to be specified on the
command line. Either one of:
* ``--build``, ``-b`` to build (existing tools are skipped);
* ``--rebuild``, ``-r`` to rebuild (existing tools are rebuilt);
* ``--delete``, ``-d`` to delete (tool target file is deleted if it exists,
its parent directory is deleted if it is empty).
* Replace CLI calls to external tools in virtual environment with API calls to
external libraries.