fix framebuffer scaling, aspect ratio

lwjgl3/src/main/java/wtf/beatrice/retrorender/lwjgl3/Lwjgl3Launcher.java

@@ -29,6 +29,7 @@ public class Lwjgl3Launcher {
         //// You may also need to configure GPU drivers to fully disable Vsync; this can cause screen tearing.
 
         configuration.setWindowedMode(640, 480);
+
         //// You can change these files; they are in lwjgl3/src/main/resources/ .
         //// They can also be loaded from the root of assets/ .
         configuration.setWindowIcon("libgdx128.png", "libgdx64.png", "libgdx32.png", "libgdx16.png");
@@ -42,4 +43,4 @@ public class Lwjgl3Launcher {
 
         return configuration;
     }
-}
+}