Fixes a bug causing newlines to disappear when a console is truncated

src/main/java/net/knarcraft/minecraftserverlauncher/userinterface/Console.java

@@ -93,7 +93,7 @@ public class Console extends KeyAdapter implements ActionListener, KeyListener {
         StringBuilder newTextBuilder = new StringBuilder();
         for (String line : oldTextList) {
             if (!line.equals("")) {
-                newTextBuilder.append(line);
+                newTextBuilder.append(line).append("\n");
             }
         }
         this.textOutput.setText(newTextBuilder.toString());