Things changed:
- make getImageFileFormat case insensitive
- use QTextEdit::dragEnterEvent instead of QAbstractScrollArea::dragEnterEvent,
- Make dragEnterEvent() and dropEvent() overrides.
This includes:
- NuulsUploader.cpp
- changing upload delay to a #define
- moving png conversion code to `boost::optional<QByteArray> convertToPng(QImage image)`
- in uploadImageToNuuls: moving content type definition to a variable, move things around a bit to eliminate an if
- in upload: adding a comment about `source->hasUrls()` and `source->urls()`, change `uploadQueue.size()` to `!uploadQueue.empty()`
- ResizingTextEdit.cpp
- changing #include order
