Some thoughts about the API:
1) Instead of `parseJSONValue` and `lexJSON`, how about static
methods `JSON.parse` and `JSON.lex`, or even a module level
functions `std.data.json.parse` etc.? The "JSON" part of the name
is redundant.
2) Also, `parseJSONValue` and `parseJSONStream` probably don't
need to have different names. They can be distinguished by their
parameter types.
3) `toJSONString` shouldn't just take a boolean as flag for
pretty-printing. It should either use something like
`Pretty.YES`, or the function should be called
`toPrettyJSONString` (I believe I have seen this latter
convention elsewhere).
We should also think about whether we can just call the functions
`toString` and `toPrettyString`. Alternatively, `toJSON` and
`toPrettyJSON` should be considered.
