OpenSystemsDevelopment / qpdf

* Handle error conditions that occur when using the object handle
  interfaces. In the past, some exceptions were not correctly
  converted to errors or warnings.
* Add more detailed information to qpdf-c.h
* Make it possible to work more explicitly with uninitialized objects

Fix typo in --rotate example

Thanks @neuhaus!

When making resources indirect in from_dr, the code was using the
wrong owning QPDF, forgetting that from_dr had already been copied
using CopyForeignObject.

When adding a QPDFObjectHandle to an array or dictionary, if possible,
check if the new object belongs to the same QPDF. This makes it much
easier to find incorrect code than waiting for the situation to be
detected when the file is written.

Also switch URLs for the qpdf and qtest websites to sourceforge.io
(https) instead of sourceforge.net (http).

Also handle direct annotation, though this is much less likely.

If not found in the field hierarchy, /Q and /DA are supposed to be
looked up in the document-level form dictionary. /DR is supposed to
only come from the document dictionary.

This results in a performance penalty of 1% to 2% when replaceObject
and swapObjects are never called and a somewhat larger penalty if they
are called, but it's worth it to avoid very confusing behavior as
discussed in depth in qpdf#507.