Fix PDF417 with binary content not producing any output with ZXing 2.0
There's two issues here:
- The QByteArray to std::wstring conversion has to use unsigned bytes, the previous code did an implicit conversion to int producing wrong results for value above 127.
- We now have to explicitly specify we are inputting binary data.
See also https://github.com/zxing-cpp/zxing-cpp/pull/557.
This fixes for example domestic Hungarian railway ticket barcodes not being shown in KDE Itinerary anymore.