Use int instead of quint8 for web-client volume interface

WebChannel interprets quint8 as character.

src/player/PlayerComponent.cpp

@@ -526,14 +526,14 @@ void PlayerComponent::setAudioDevice(const QString& name)
 }
 
 ///////////////////////////////////////////////////////////////////////////////////////////////////
-void PlayerComponent::setVolume(quint8 volume)
+void PlayerComponent::setVolume(int volume)
 {
   // Will fail if no audio output opened (i.e. no file playing)
   mpv::qt::set_property_variant(m_mpv, "volume", volume);
 }
 
 ///////////////////////////////////////////////////////////////////////////////////////////////////
-quint8 PlayerComponent::volume()
+int PlayerComponent::volume()
 {
   QVariant volume = mpv::qt::get_property_variant(m_mpv, "volume");
   if (volume.isValid())

src/player/PlayerComponent.h

@@ -60,8 +60,8 @@ public:
   Q_INVOKABLE virtual void play();
   
   /* 0-100 volume 0=mute and 100=normal */
-  Q_INVOKABLE virtual void setVolume(quint8 volume);
-  Q_INVOKABLE virtual quint8 volume();
+  Q_INVOKABLE virtual void setVolume(int volume);
+  Q_INVOKABLE virtual int volume();
 
   // Returns a QVariant of the following format:
   // QVariantList                   (list of audio device entries)