Improve ant walking speed

Editor/ClusterViewer.cs

@@ -503,6 +503,9 @@ namespace NanoBrain {
             }
 
             protected void DrawOutputs(Vector2 parentPos, float size) {
+                if (this.currentCluster == null)
+                    return;
+                    
                 // Determine the maximum value in this layer
                 // This is used to 'scale' the output value colors of the nuclei
                 float maxValue = 0;