Disable the plugin instead of just returning, add a missing Logger

src/me/libraryaddict/disguise/LibsDisguises.java

@@ -48,11 +48,13 @@ public class LibsDisguises extends JavaPlugin {
                 getLogger().severe("This will be released free two weeks after all bugs have been fixed!");
                 getLogger().severe("If you've already purchased the plugin, place the purchased jar inside the " +
                         "Lib's Disguises plugin folder");
+                getPluginLoader().disablePlugin(this);
                 return;
             }
         } else {
             getLogger().severe("You're using the wrong version of Lib's Disguises for your server! This is " +
                     "intended for 1.13!");
+            getPluginLoader().disablePlugin(this);
             return;
         }
 

src/me/libraryaddict/disguise/disguisetypes/MetaIndex.java

@@ -432,7 +432,7 @@ public class MetaIndex<Y> {
         toPrint.sort(String.CASE_INSENSITIVE_ORDER);
 
         for (String s : toPrint) {
-            System.out.println(s);
+           DisguiseUtilities.getLogger().info(s);
         }
     }