add splashscreen for mobile-dev

forge-gui-android/src/forge/app/Main.java

@@ -640,6 +640,11 @@ public class Main extends AndroidApplication {
             System.exit(0);
         }
 
+        @Override
+        public void closeSplashScreen() {
+            //only for desktop mobile-dev
+        }
+
         @Override
         public boolean isTablet() {
             return isTablet;