FIX(client,positional-audio): Prevent min distance >= max distance

This kind of setup seems nonsensical and is therefore prevented by
automatically adapting the other threshold accordingly.

src/mumble/AudioConfigDialog.cpp

@@ -856,20 +856,32 @@ void AudioOutputDialog::on_qcbLoopback_currentIndexChanged(int v) {
 void AudioOutputDialog::on_qsMinDistance_valueChanged(int value) {
  QSignalBlocker blocker(qsbMinimumDistance);
  qsbMinimumDistance->setValue(value / 10.0f);
+
+ // Ensure that max distance is always a least 1m larger than min distance
+ qsbMaximumDistance->setValue(std::max(qsbMaximumDistance->value(), (value / 10.0) + 1));
 }
 
 void AudioOutputDialog::on_qsbMinimumDistance_valueChanged(double value) {
  QSignalBlocker blocker(qsMinDistance);
  qsMinDistance->setValue(value * 10);
+
+ // Ensure that max distance is always a least 1m larger than min distance
+ qsMaxDistance->setValue(std::max(qsMaxDistance->value(), static_cast< int >(value * 10) + 1));
 }
 
 void AudioOutputDialog::on_qsMaxDistance_valueChanged(int value) {
  QSignalBlocker blocker(qsbMaximumDistance);
  qsbMaximumDistance->setValue(value / 10.0f);
+
+ // Ensure that max distance is always a least 1m larger than min distance
+ qsbMinimumDistance->setValue(std::min(qsbMinimumDistance->value(), (value / 10.0) - 1));
 }
 void AudioOutputDialog::on_qsbMaximumDistance_valueChanged(double value) {
  QSignalBlocker blocker(qsMaxDistance);
  qsMaxDistance->setValue(value * 10);
+
+ // Ensure that max distance is always a least 1m larger than min distance
+ qsMinDistance->setValue(std::min(qsMinDistance->value(), static_cast< int >(value * 10) - 1));
 }
 
 void AudioOutputDialog::on_qsMinimumVolume_valueChanged(int value) {