Extend Documentation on Process::SubProcess::Group

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This development extends the documentation in the on-going effort documented at:
Enhance Documentation

This documents methods in Process::SubProcess::Group:

• setTimeout()
• Wait()

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debugging output in the Process::SubProcess::Group test will give also clear insights into the error reported at:
Process::SubProcess::Group Timeout Test fails

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All existing test have passed. The development is ready to be released.