Set default tileset size to 4x4

android/gradle.properties

 org.gradle.jvmargs=-Xmx1536M
 android.useAndroidX=true
 android.enableJetifier=true
-app.versionName=0.0.23
-app.versionCode=23
+app.versionName=0.0.24
+app.versionCode=24

lib/provider/data.dart

@@ -5,7 +5,7 @@ import '../entities/tile.dart';
 class Data extends ChangeNotifier {
 
   // application configuration
-  int _tilesCount = 3;
+  int _tilesCount = 4;
 
   // application data
   List _images = [];