Improve the file delegate

- cleaner code
- supports stopping downloads
- utilises the mimetype in order to display an icon
- better size formatting
- tooltips

src/controller.cpp

@@ -610,7 +610,7 @@ void Controller::openOrCreateDirectChat(NeoChatUser *user)
 
 QString Controller::formatByteSize(double size, int precision) const
 {
-    return KFormat().formatByteSize(size, precision);
+    return QLocale().formattedDataSize(size, precision);
 }
 
 QString Controller::formatDuration(quint64 msecs, KFormat::DurationFormatOptions options) const