Post-merge fixups

In particular, act as if a spellbook has been discovered during tooltip
generation if player is null. This allows JEI to index all the spell
names.

src/main/java/electroblob/wizardry/item/ItemArmourUpgrade.java

@@ -13,6 +13,8 @@ import net.minecraft.world.World;
 import net.minecraftforge.fml.relauncher.Side;
 import net.minecraftforge.fml.relauncher.SideOnly;
 
+import javax.annotation.Nullable;
+
 public class ItemArmourUpgrade extends Item {
 
 	public ItemArmourUpgrade(){