added test for grid

build.gradle

src/main/java/app/SimulatorApplication.java

src/main/java/app/SimulatorMain.java

src/main/java/controller/Controller.java

src/main/java/controller/PersistentToggleGroup.java

src/main/java/model/Board.java

src/main/java/model/FirefighterBoard.java

src/main/java/model/ModelElement.java

src/main/java/module-info.java

src/main/java/util/Position.java

src/main/java/view/FirefighterGrid.java

src/main/java/view/Grid.java

src/main/java/view/ViewElement.java

src/main/resources/view/DarkTheme.css

src/main/resources/view/view.fxml

src/test/java/model/FirefighterBoardTest.java

src/test/java/view/FirefighterGridTest.java