OpenSystemsDevelopment / qpdf

Create an alternative to getJSON to allow an object handle to be written as JSON without the overhead of creating a JSON object.

Also, name the type QPDFValue::Description.

Remove parameters and return the description.

Set parsed offset at the same time as setting description.

Avoid dynamic casting.

Add optional parameter shallow. Change logic errors to runtime errors.

QPDFValueProxy wasn't a good name for it. We decided the evil of
having the header file be named QPDFObject_private.hh was less than
the evil of having the class be named something other than what it
should have been named.

Preparing to change the class name back to QPDFObject