Make JSON parsing more lazy

[mikekap]

This patch does 2 things:

• Fixes the ability to set *chunk-size* for lazy streams (the binding can now be set around the json/parse-stream call rather than around whatever seq-consumption code you were using).
• "Fixes" the ability to have a very lazy JSON array-stream that only produces one "message" at a time.

For context on the latter, I have a (weird) protocol that looks like this:

[
{"type": "handshake", "id": 0}
, {"type": "command", "id": 1}
, {"type": "command", "id": 2}
...
]

The issue is the producer of this JSON is fully lazy - i.e. it outputs one , {"type": "blah"} command at a time and "waits" for a response. Cheshire can almost parse this, and with this change it can fully parse this (assuming you set *chunk-size* to 1). The root cause is just an issue with calling nextToken before returning the element in the sequence (those two should be reversed).