OpenSystemsDevelopment / qpdf

As a rule, we should avoid conditional compilation is it always causes
code paths that are sometimes not even seen lexically by the compiler.
Also, we want the actual code being fuzzed to be as close as possible
to the real code. Conditional compilation is suitable to handle
underlying system differences.

Instead, favor configuration using callbacks or other methods that can
be triggered in the places where they need to be exercised.

Ensure objects with impossibly large ids are ignored.

Also, apply limit in dct_fuzzer

Amend fuzz future

Refactor QPDF::parse_xrefEntry

QPDF::processXRefStream

Change the processed Index array to a vector of <first object, number of
entries> pairs.

Create set without creation of an intermediate vector.

Move reading of the entry from read_xrefTable to parse_xrefEntry.

Split parse_xrefEntry into two new methods read_xrefEntry and
read_bad_xrefEntry. read_xrefEntry is optimised for reading
correct entries. To handle incorrect entries it calls read_bad_xrefEntry,
which is largely unchanged from parse_xrefEntry.

Use QPDF_Stream::writeStreamJSON.
Factor out the json_stream_data == qpdf_sj_file case.

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

Create a simple utility class for writing JSON to a pipeline.

The code accepted values other than /Yes but still used /Yes as the
checked value instead of obeying the normal appearance dictionary.

Accept --file and --range as named parameters in additional to
allowing positional arguments. This is in preparation for adding
additional flags.