Order & cart refactoring

[bethrezen]

Actual details on this task: http://redmine.devgroup.su/issues/4

• OOP-styled cart
• OOP-styled order
• Event-based notifications and actions
• Store product price in OrderItem, update it if quantity changes
• Don't empty cart on payment stage Cart should NOT be emptied on payment selection stage #152
• Configurable order workflow Configurable order workflow #184
• Ability to customize E-Mail notifications for each workflow step, both for managers and buyer in backend(notification templates are stored in plain php files)
• Configurable option to update product prices of unfinished order on workflow steps
• Ability to force updating of product prices in backend for order
• Initiate payment on order with custom price & payment type from backend(if payment handler supports it, ie. for platron)
• Order creation from backend
• Adding custom items to order in backend(ie. non-existing products in catalog)
• Support additional order data(properties)
• Promo Codes, discounts support Promocode generation and discounts #124
• Special case - no products in warehouse
• Taxes support
• ShippingOption improvements
  • Refactor ShippingOption for using unified classes for handling 'Delivery method' + Delivery cost calculation #125
  • New special delivery type - self-pick from warehouse Multiple warehouses #174
  • Support order products total weight
  • Image for delivery method
  • Delivery time
  • Available for user groups
  • Conditional price calculation
• Measurement units support for product