Added setContents() to Inventory.

By: sk89q <the.sk89q@gmail.com>

paper-api/src/main/java/org/bukkit/inventory/Inventory.java

@@ -52,6 +52,13 @@ public interface Inventory {
      */
     public ItemStack[] getContents();
 
+    /**
+     * Set the inventory's contents
+     * 
+     * @return All the ItemStacks from all slots
+     */
+    public void setContents(ItemStack[] items);
+
     /**
      * Check if the inventory contains any ItemStacks with the given materialId
      *