Added AddMethod and Default x,y,width,height on Add

src/Enums/AddMethod.ts

@@ -0,0 +1,10 @@
+/**
+ * Add method when creating a container
+ * - Append will append to the last children in list
+ * - Insert will always place it at the begining
+ * (default: Append)
+ */
+export enum AddMethod {
+  Append,
+  Insert
+}