Consistent formatting and additional array detail

[tobyhodges]

Addresses common-workflow-language/common-workflow-language#318

• Made array formatting in record.cwl consistent
• Added short explanation of YAML array formats, in input files and in CWL descriptions
• Added short explanation of empty JSON object in empty.yml (should this be empty.json really? How does one write an explicitly empty YAML file/object?)

[tobyhodges]

Ok, I'm now not actually sure that what I say about the requirements having to be specified with - is accurate. Certainly that's not how it's done here: https://github.com/ProteinsWebTeam/ebi-metagenomics-cwl/blob/19fce22aa01f8d7d068dc7f11f5e0a3bdb9cf854/tools/InterProScan5.21-60.cwl#L13

I guess I need to read the YAML specification properly...

[tobyhodges]

Ok, the descriptions/explanations are a bit clearer now.