Split Order model into Invoice and Order, so one Invoice can have multiple Orders.
Minor adjustment to admin and models.
Move Customer info into Invoice instead of Order.
Add order_items property for intermediary objects accessing.
Update new_order to fit new model.
Update show.html template to meet new context and model.
Rename view names and fix show_invoice.
Merge pull request #8 from gregwym/split-order

Adjust Order model to fit multi-order within single invoice.