fix issue where building stats don't update while the building is kept selected

src/ui/SelectedBuildingPanel.h

@@ -5,8 +5,10 @@
 
 #include <QWidget>
 
+#include "Building.h"
 #include "EntityId.h"
 #include "GameConfig.h"
+#include "Tick.h"
 
 class Simulation;
 class QLabel;
@@ -24,6 +26,7 @@ public:
 
 public slots:
     void onSelectionChanged(const std::vector<EntityId>& ids);
+    void onStateUpdated(Tick tick, int blocks, double speed);
 
 private slots:
     void onRecipeChanged(int comboIndex);
@@ -35,6 +38,7 @@ private:
     void buildEmpty();
     void buildSingle(EntityId id);
     void buildMulti(const std::vector<EntityId>& ids);
+    void refreshBuffers(const Building* b);
 
     Simulation*        m_sim;
     const GameConfig*  m_config;