[wip] Spree::Klarna::Order:
. Spree::Klarna::Order represents Klarna's checkout order on our end
. Manages the properties that are needed to make api-requests
. Manages the properties that Klarna sets and we should maintain
. Keeps a reference to Spree:Order, and fetches cart related properties from it
. Keeps a reference to Spree::Klarna::CheckoutHandler object manages the api request/responses
Merge pull request #1 from zerothabhishek/klarna_order_and_spec

[wip] Spree::Klarna::Order