4.0 pre-release, do not use other than for testing.
SECURITY IMPLICATION: this release enables allow_nonref by default for compatibnility with RFC 7159 and newer. See "old" vs. "new" JSON under SECURITY CONSIDERATIONS.
reworked the "old" vs. "new" JSON section.
add ->boolean_values to provide the values to which booleans decode (requested by Aristotle Pagaltzis).
decode would wrongly accept ASCII NUL characters instead of reporting them as trailing garbage.
work around what smells like a perl bug w.r.t. exceptions thrown in callbacks.
incremental parser now more or less respects allow_nonref.