Modify jIO API to keep user data not modified.
    jIO.get({"_id": "foo"} -> jIO.get("foo")
    jIO.remove({"_id": "foo"} -> jIO.remove("foo")
    jIO.post({"title": "bar"}) -> jIO.post({"title": "bar"})
    jIO.put({"_id": "foo", "title": "bar"}) -> jIO.put("foo", {"title": "bar"})
    jIO.getAttachment({"_id": "foo", "_attachment": "enclosure"} -> jIO.get("foo", "enclosure")
    jIO.removeAttachment({"_id": "foo", "_attachment": "enclosure"} -> jIO.remove("foo", "enclosure")
    jIO.putAttachment({"_id": "foo", "_attachment": "enclosure", "_blob": blob} -> jIO.remove("foo", "enclosure", blob)

jIO.get does not return an _id attribute anymore.