Support peek

src/main/java/org/warp/commonutils/type/FastUtilStackWrapper.java

@@ -26,6 +26,11 @@ public class FastUtilStackWrapper<T> implements Stack<T>, Collection<T> {
 		return this.stack.pop();
 	}
 
+	@Override
+	public T peek(int n) {
+		return this.stack.peek(n);
+	}
+
 	@Override
 	public int size() {
 		return collection.size();