Periodically purge expired elements from recently seelected quests repo

Plugins/mineplex-questmanager/src/mineplex/quest/daemon/QuestManager.java

@@ -151,6 +151,9 @@ public class QuestManager extends Thread
         {
             while (_alive)
             {
+                // purge recently selected quests repo of expired entries
+                _recentlySelectedQuestsRepo.clean();
+                
                 LocalDate now = LocalDate.now(EST_TIMEZONE);
                 // check if date has changed; if so we need to choose new quests
                 if (_currentDate.isBefore(now) || _activeQuests.isEmpty())