OpenSystemsDevelopment / qpdf

Avd xcsv brvtns.

Now --json-output just changes defaults. Allow output file with --json.

Add additional parameters that will be needed to call QPDF::writeJSON
in partial mode.

* 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.

Also add stubs for top-level QPDF methods (createFromJSON,
updateFromJSON)

Update getJSON() methods and calls to them

Testing json against schema requires an in-memory copy, so do it only
when requested by the test suite.

It was being run at configuration time, not build time.

This is to catch pull requests that make changes that would affect
automatically generated job files without including those
modifications.

This makes it much more convention to use the initializeFromArgv
functions since you can use string literals.

For optional parameter/choices, generate an overloaded config method
that takes no arguments. This makes it possible to convert from a bare
argument to one that takes an optional parameter without breaking
binary compatibility.

Changing from bool requiring true to string requiring the empty string
is more consistent with the CLI and makes it possible to add an
optional parameter or choices later without breaking compatibility.

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.