A parse error in stream data in which stream data contained a nested
object would cause a crash because qpdf was not correctly updating its
internal state. Rework the QPDF json reactor to not be sensitive to
parse errors in this way.
* Replace --create-from-json=file with --json-input, which causes the
regular input to be treated as json.
* Eliminate --to-json
* In --json=2, bring back "objects" and eliminate "objectinfo". Stream
data is never present.
* In --json-output=2, write "qpdf-v2" with "objects" and include
stream data.
