Add donor perks and tweak generalise rendering of healing totem

src/main/java/electroblob/wizardry/util/Box.java

@@ -0,0 +1,33 @@
+package electroblob.wizardry.util;
+
+/**
+ * A very simple container for a single object of a given type {@code T} (referred to as the <i>contents</i>). Allows
+ * fixed-size collections to be made using their immutable (or unmodifiable) counterparts. This is particularly useful
+ * for maps with a fixed set of keys but whose values may be changed.
+ */
+public class Box<T> {
+
+	private T contents;
+
+	public Box(T contents){
+		this.contents = contents;
+	}
+
+	/** Returns the contents of this box. */
+	public T get(){
+		return contents;
+	}
+
+	/** Sets the contents of this box to the given object. */
+	public void set(T contents){
+		this.contents = contents;
+	}
+
+	// Probably misleading since methods like this generally imply immutability, which is exactly what we're not doing
+
+//	/** Creates a new box with the given contents. This is just a static factory method that calls the constructor. */
+//	public static <T> Box<T> of(T contents){
+//		return new Box<>(contents);
+//	}
+
+}