RT #35194 'ack' now accepts arbitrary headers
summary of changes since 0.46
fix RT #90100, add reply-to frame accessor
fix RT #80079 pick first value of repeated headers
test failover, investigating RT #96766 and #96767
fixup! fbf8214
some fixes from RT #68160

limit reconnect attempts, ignore SIGPIPE while writing, fail more
gracefully when the connection dies while reading inside one of the
public methods
docs, and version bump
preparing for release