better management of operational task arguments

ewoksppf/bindings.py

ewoksppf/tests/test_ppf_workflow1.py

ewoksppf/tests/test_ppf_workflow10.py

ewoksppf/tests/test_ppf_workflow11.py

ewoksppf/tests/test_ppf_workflow12.py

ewoksppf/tests/test_ppf_workflow13.py

ewoksppf/tests/test_ppf_workflow14.py

ewoksppf/tests/test_ppf_workflow15.py

ewoksppf/tests/test_ppf_workflow16.py

ewoksppf/tests/test_ppf_workflow17.py

ewoksppf/tests/test_ppf_workflow18.py

ewoksppf/tests/test_ppf_workflow19.py

ewoksppf/tests/test_ppf_workflow20.py

ewoksppf/tests/test_ppf_workflow3.py

ewoksppf/tests/test_ppf_workflow6.py

ewoksppf/tests/test_ppf_workflow7.py

ewoksppf/tests/test_ppf_workflow8.py

ewoksppf/tests/test_ppf_workflow9.py