json4s/json4s — pull request #123 by msturm (2014-05-01 11:18:00+00:00)
Title: #114 Don't produce invalid json when the first field is a JNothing

Fix a bug which caused
JObject(JField("foo", JNothing), JField("bar", JString("something")) :: Nil)

to be rendered as {, "bar":"something"}
which is invalid.