OpenSystemsDevelopment / qpdf

This change works around STL problems with Embarcadero C++ Builder
version 10.2, but std::vector is more common than std::list in qpdf,
and this is a relatively new API, so an API change is tolerable.

Thanks to Thorsten Schöning <6223655+ams-tschoening@users.noreply.github.com>
for the fix.

Now uses QPDFOutlineDocumentHelper and QPDFOutlineObjectHelper.

For std::string and std::vector, replace operator[] with at.  This was
done using an automated process.  See README.hardening for details.

In internal code and examples, replace calls to getObjectID() and
getGeneration() with calls to getObjGen() where possible.

git-svn-id: svn+q:///qpdf/trunk@686 71b93d88-0707-0410-a8cf-f5a4172ac649

git-svn-id: svn+q:///qpdf/trunk@607 71b93d88-0707-0410-a8cf-f5a4172ac649

git-svn-id: svn+q:///qpdf/trunk@599 71b93d88-0707-0410-a8cf-f5a4172ac649