nevow.json serializes some line terminators such that Athena cannot deserialize them in the browser

JSON encoded bytes may include literal (that is, UTF-8 encoded) U+2028 or U+2029. However, JavaScript string literals may not. See http://timelessrepo.com/json-isnt-a-javascript-subset for any more detail that may be interesting.

Athena's JavaScript parser (browser-side JavaScript eval) cannot parse these literals. If we emit escaped versions of the line terminators, the parser won't need to change.