This example illustrates how to running makeflow with the help of umbrella.

The user can specify the umbrella binary through the `--umbrella-binary`
option; and specify the umbrella spec through the `--umbrella-spec` option.

To test makeflow with umbrella using local execution engine:
$ makeflow --umbrella-binary $(which umbrella) --umbrella-spec convert_S.umbrella example.makeflow

To test makeflow with umbrella using wq execution engine:
$ makeflow -T wq --umbrella-binary $(which umbrella) --umbrella-spec convert_S.umbrella example.makeflow

To test the case when `--wrapper` and `--umbrella-spec|binary` are used at the same time:
$ makeflow --wrapper 'time -p /bin/sh -c []'  --umbrella-binary $(which umbrella) --umbrella-spec convert_S.umbrella example.makeflow
$ makeflow -T wq --wrapper 'time -p /bin/sh -c []'  --umbrella-binary $(which umbrella) --umbrella-spec convert_S.umbrella example.makeflow
