rename App to CalcApp

pom.xml

@@ -95,7 +95,7 @@
                 <!-- Default configuration for running -->
                 <!-- Usage: mvn javafx:run -->
                 <configuration>
-                    <mainClass>app.App</mainClass>
+                    <mainClass>app.CalcApp</mainClass>
                 </configuration>
             </plugin>
         </plugins>

src/main/java/app/App.java → src/main/java/app/CalcApp.java

@@ -11,7 +11,7 @@ import java.io.IOException;
 /**
  * JavaFX App
  */
-public class App extends Application {
+public class CalcApp extends Application {
 
     @Override
     public void start(Stage stage) throws IOException {