This is now the default way to play back sound under Windows. The other one,
"Use external program", was also made available there. The old method of audio
playback under Windows (via PlaySound) was completely removed.
Since Phonon uses DirectShow as a backend under Windows, all file types
supported by it should now play back. Therefore, the previous limitation to
just .wav files is now lifted.
Since Phonon is only available starting from Qt 4.6.0 under Windows, no older
versions of Qt are supported anymore there.