Add Use Cases and Requirements

Merge pull request json-schema-org#1247 from json-schema-org/changing…

…-property-key-names-in-output-format

Changing property key names in output format

Fix organization tag location

Fix organization tag location

Update draft identifiers for 2020-12 patch release

Add or remove defaults as appropriate including where redundant (json…

…-schema-org#1006)

- Remove `default` from all subschemas that recursively-reference #meta
- Add `default to `dependencies`

Remove, e.g. when evaluating the "not" keyword, the subschema inside it should *not* be true, as that would produce a false result from this keyword.

Clarify how JSON Schema works with a superset of the defined data model

Clarify how JSON Schema works with a superset of the defined data model