NewJSONScanner return a new Scanner{} interface for parsing JSON string.

Y is root Parser, usually called as `s` in CFG theory.

JSONScanner implements parsec.Scanner{} interface used as custom scanner for parsing JSON string.

False is alias for string type denoting JSON `false`.

Null is alias for string type denoting JSON `null`.

Num is alias for string type denoting JSON `number`.

String is alias for string type denoting JSON `string`.

True is alias for string type denoting JSON `true`.