Use seconds instead of milliseconds for the update interval

resources/windows/MainWindows.fxml

@@ -52,10 +52,10 @@
     </center>
     <bottom>
         <FlowPane>
-            <Text>Millis per tick :</Text>
+            <Text>Update delay :</Text>
             <Spinner fx:id="updateInterval">
                 <valueFactory>
-                    <javafx.scene.control.SpinnerValueFactory.IntegerSpinnerValueFactory min="10" max="2000" />
+                    <javafx.scene.control.SpinnerValueFactory.DoubleSpinnerValueFactory min="0.5" max="100" amountToStepBy="0.5" />
                 </valueFactory>
             </Spinner>
             <ToggleButton fx:id="autoUpdate" text="Auto update" />