OpenSystemsDevelopment / qpdf

Using search and replace.

Add new convenience class QPDFObjGen::Guard

Code tidy re-throwing of exceptions

Warn if catalog type entry is invalid (fixes #810)

Avoid copying exceptions.

Improve --optimize-images to find images nested within XObjects

Also, change QPDFJob to use unique_ptr<QPDF> instead of shared pointers.

Also, inline method and add optional parameter error_msg.

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

from "qpdf-v2" to "qpdf": [..., ...]

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

Code tidy : replace 0 with nullptr or true