add tracing for performance profiling

src/lib/sim/BeltSystem.cpp

@@ -3,6 +3,7 @@
 #include <algorithm>
 
 #include "Tick.h"
+#include "tracing.h"
 
 // ---------------------------------------------------------------------------
 // Helpers
@@ -396,6 +397,7 @@ void BeltSystem::clearTiles(const std::vector<QPoint>& tiles)
 
 void BeltSystem::tick()
 {
+	TRACE();
     advanceProgress();
     advanceTunnelProgress();
     moveItemsToNextTile();
@@ -960,3 +962,4 @@ void BeltSystem::forEachVisualItem(QRect viewportTiles,
         }
     }
 }
+