Load island difficulty when loading islandworld

plugin/src/main/java/com/alttd/cometskyblock/worldgenerator/MasterWorldGenerator.java

@@ -115,6 +115,7 @@ public class MasterWorldGenerator {
             return null;
         }
 
+        newIsland.setDifficulty(Difficulty.NORMAL); // TODO - island options to set difficulty
         return newIsland;
     }