Cleaned up orderservice and iorderservice a bit. (No reason to return List when IEnumerable is enough, ctor injected IOrderrepsitory instead of instatiating it every single time.
Refactored slightly.
Moved non-controller classes to more appropriate namespaces.
Added first unit tests for payment complete handler, caused refactoring of some customer and order related classes.
Some refactoring of paymentcompletehandler. Removed superfluous methods from interface.