OpenSystemsDevelopment / qpdf

Also, fix test cases.

The new method is temporarily an (almost) complete copy of parse, which is
temporarily (almost) unchanged.

Fixes #864. QPDFTokenizer::getValue originally had a std::string_view
return type, which was changed to std::string without removing some
unnecessary string creation.

When a user accepts a spelling word, the word appears in a
.idea/dictionaries/$user.xml where $user is their username. A user has
control over "their "words, but all users see all words. For qpdf, we
probably want all the "official" words in qpdf.xml. This should be
automated.

provide link to _Crypto providers_

Fix #1028