Starting work on the OrderView interface.
Starting work on Purchase View delegation design.
Complete delegation design pattern

- Completed delegation design pattern for order completion.
Refactoring product / order processing
Refining order / receipt processing
Adding order footer subtotal to OrderView
Midway completion milestone.

- Refactored order generation factory
- Implemented tuple return type from receipt engine.
Building Receipt View

- Adding blur effect to final presentation window.
Added the receipt view as a blur subview
Reorganized file structure