Closes #8: Added support for setting visibility of side menu and button

Author: mlopezFC

src/main/java/com/flowingcode/addons/applayout/AppHeader.java

@@ -59,5 +59,9 @@ public AppToolbar getAppToolbar() {
 	public void setToolbarIconButtons(MenuItem[] menuItems) {
 		appToolbar.setToolbarIconButtons(menuItems);
 	}
+
+	public void setMenuIconVisible(boolean visible) {
+		appToolbar.setMenuIconVisible(visible);
+	}
 
 }

src/main/java/com/flowingcode/addons/applayout/AppLayout.java

@@ -67,6 +67,15 @@ public void clearMenuItems() {
 	public void setToolbarIconButtons(MenuItem... menuItems) {
 		header.setToolbarIconButtons(menuItems);
 	}
+	
+	public void setMenuVisible(boolean visible) {
+		drawer.setVisible(visible);
+		header.setMenuIconVisible(visible);
+	}
+	
+	public boolean isMenuVisible() {
+		return drawer.isVisible();
+	}
 
 	@Override
 	public void configurePage(InitialPageSettings settings) {

src/main/java/com/flowingcode/addons/applayout/AppToolbar.java

@@ -70,5 +70,9 @@ private List<PaperIconButton> createToolbarIconButtons(MenuItem[] menuItems) {
         return result;
 }
 
+	public void setMenuIconVisible(boolean visible) {
+		menu.setVisible(visible);
+	}
+
 
 }

src/test/java/com/flowingcode/addons/applayout/DemoView.java

@@ -22,7 +22,6 @@
 
 import com.flowingcode.addons.applayout.menu.MenuItem;
 import com.vaadin.flow.component.html.H3;
-import com.vaadin.flow.component.icon.VaadinIcon;
 import com.vaadin.flow.component.notification.Notification;
 import com.vaadin.flow.component.orderedlayout.VerticalLayout;
 import com.vaadin.flow.router.Route;
@@ -45,6 +44,7 @@ public DemoView() {
 		app.setMenuItems(createMenuItems());
 
 		app.setToolbarIconButtons(new MenuItem("Delete", "delete", () -> Notification.show("Delete action")),
+				new MenuItem("Hide/Show Menu", "clear", () -> app.setMenuVisible(!app.isMenuVisible())),
 				new MenuItem("Search", "search", () -> Notification.show("Search action")),
 				new MenuItem("Close", "close", () -> Notification.show("Close action")));
 
@@ -55,7 +55,7 @@ private MenuItem[] createMenuItems() {
 		MenuItem mi = new MenuItem("Say hello", "star", () -> showContent("Hello!"));
 		return new MenuItem[] {mi ,
 				new MenuItem("About", "cloud", () -> showContent("About")),
-				new MenuItem("Clear Items", "star", () -> app.clearMenuItems()), 
+				new MenuItem("Clear Items", "clear", () -> app.clearMenuItems()), 
 				new MenuItem("Change Text & Icon", "cloud", () -> {
 					if (mi.getIcon().equals("star")) {
 						mi.setIcon("cloud");