OpenSystemsDevelopment / qpdf

Version 1.8 allows QTC::TC to break across lines.

This is so it will fit on one line after a qtest upgrade allows us to
split lines.

This was mainly to get comments about defaults out of constructor
initializer lists where their fragile when a code formatter is being
used.

We have been keeping main's version at the last released version, but
starting now, main's version will always be whatever it would be if
a release were cut from the tip of main.

Some people don't know what CI is, so remove use of that abbreviation
when it doesn't add any value.

The PDF spec only allows UTF-16BE, but most readers seem to accept
UTF-16LE as well, so now qpdf does too.

This was unintended behavior that was added back for backward
compatibility. It is intentionally undocumented.

There are codepoints in PDFDoc that are not valid UTF-8 but map to
valid UTF-8. We were handling those correctly with bidirectional
mapping.

However, if those same code points appeared in UTF-8, where they have
no meaning, they were left as fixed points when converting to PDFDoc,
where they do have meaning. This change recognizes them as errors.

Convert loops to use range-based for statements.
Simplify the extract_bookmarks function.

Remove test for type == /XObject in QPDFObjectHandle::isFormXObject
as type value is optional (as per spec 8.10.2).

Replace code to test for /Form in QPDFJob::shouldRemoveUnreferencedResources
with a call to isFormXObject.

Sometimes someone may build only a subset of the documentation. The
logic has to be conditional upon whether it exists, not whether it is
built, since we pull pre-built docs in for CI installation.