Ensure label visibility

Make sure that labels are always shown by setting the row wrap policy of
the form layout to wrap long rows.

src/core/audio/AudioSdl.cpp

@@ -305,6 +305,7 @@ AudioSdl::setupWidget::setupWidget( QWidget * _parent ) :
 	AudioDeviceSetupWidget( AudioSdl::name(), _parent )
 {
 	QFormLayout * form = new QFormLayout(this);
+	form->setRowWrapPolicy(QFormLayout::WrapLongRows);
 
 	m_playbackDeviceComboBox = new QComboBox(this);