Fix for #264

Bees coming from hives trigger creature spawn event with SpawnReason BEEHIVE, however when using Paper's Entity#getEntitySpawnReason they retain their original spawn reason.

We could change it so that the spawn event uses the Paper method for checking blacklists etc, but there would be problems for spigot users, requiring checks for use of Paper. But if an entity was previously destacked - they would become stacked again.

(description copied from 50d6ee0)

src/main/java/uk/antiperson/stackmob/listeners/SpawnListener.java

@@ -24,6 +24,11 @@ public void onSpawn(CreatureSpawnEvent event) {
         if (!(event.getEntity() instanceof Mob)) {
             return;
         }
+        if (event.getEntity() instanceof Bee) {
+            if (event.getSpawnReason() == CreatureSpawnEvent.SpawnReason.BEEHIVE) {
+                return;
+            }
+        }
         sm.getScheduler().runTask(sm, event.getEntity(), () -> {
             if (sm.getEntityManager().isStackedEntity(event.getEntity())) {
                 StackEntity stackEntity = sm.getEntityManager().getStackEntity(event.getEntity());