Use getItemInMainHand()

Add 1.9 blocks to be detected for experience rewards.
Add experience rewards for the Chorus plant.
Add experience rewards for the Shulker mob.

src/main/java/com/gmail/nossr50/util/ItemUtils.java

@@ -589,6 +589,8 @@ public final class ItemUtils {
             case WHEAT:
             case SEEDS:
             case CARROT_ITEM:
+            case CHORUS_FRUIT:
+            case CHORUS_FLOWER:
             case POTATO_ITEM:
             case NETHER_WARTS:
             case BROWN_MUSHROOM: