[#209] Make it possible to add different variants products into the 
wishilist. Moreover, Add the message stack for the wishlist add action.
[#209]Add the language definition for the wishlist add action
[#209]Update the variants wishlists products table. I don't know why 
the wishlists_id and wishlists_products_id column result in the sql 
error. In this case, i have to rename the two column to clear the error