OpenSystemsDevelopment / qpdf

Also add new fuzz test case.

Code failed to allow for QPDF::getCompressibleObjSet deleting objects
from the object cache in case of multiple entries for the same object id.

Add fuzz test case 68668.

Create set without creation of an intermediate vector.

Apply various Clang-Tidy rules

Using search and replace.

Set indent differently for qdf and non-qdf files.
Combine with preceding newline for qdf files.

Also, uninitialize QPDFWriter::Members members.

Use string_view parameters and call pipeline write methods directly.

Move test for m->linearized outside loop.

I decided that it's actually fine to copy a direct object to another
QPDF. Even if we eventually prevent a QPDFObject from having multiple
parents, this could happen if an object is moved.

For consistency with similar methods, e.g. replaceObject.

Code tidy : replace 0 with nullptr or true