Changes priority to Monitor, and skips checking for matches if the player is exempt from payment

src/main/java/net/knarcraft/paidsigns/listener/SignListener.java

@@ -17,9 +17,9 @@ import java.util.List;
  */
 public class SignListener implements Listener {
 
-    @EventHandler(priority = EventPriority.LOW)
+    @EventHandler(priority = EventPriority.MONITOR)
     public void onSignChange(SignChangeEvent event) {
-        if (event.isCancelled()) {
+        if (event.isCancelled() || event.getPlayer().hasPermission("paidsigns.paymentexempt")) {
             return;
         }