Changes in qdir/qfile between qt3 and qt4

The current and parent directory identifiers ( . and .. ) behavior seems to have changed between Qt 3 and Qt 4.

In Qt 3 a call to QDir::dirName() or QDir::path() where the QDir has been set with .setPath(..) will return the name of the directory, but in Qt 4 these calls return the identifier .. instead of the resolved path.

This should be mentioned in the Porting documentation.