* 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.
Flatten everything to make it easier to map command-line flags to
json. The old structure was an illusion anyway because there was no
mechanism to enforce that things were in the right place. This also
helps with future flexibility.
The code was assuming everything was happening inside dictionaries.
Instead, make the dictionary key handler creatino explicit only when
iterating through dictionary keys.
Jay Berkenbilt