#429: README.md, add 'jsonschema' subsection
#429: README.md, initial definition of 'jsonschema' subsection
#429: README.md, further define 'jsonschema'
#429: add 'additional documentation'
#429: README.md, specific 'JSON Schema' implementation
#429: README.md, fix typo
#429: README.md, minor language change
#429: README.md, minor language change
#429: README.md, add links
Merge pull request #605 from jeff1evesque/doc_jsonschema

#429: Documentation - 'jsonschema'