* Modularity improvements:
  * Moved all Grouped Product functionality to newly created module GroupedProduct
  * Moved Multishipping functionality to newly created module Multishipping
  * Extracted Product duplication behavior from Product model to Product\Copier model
  * Replaced event "catalog_model_product_duplicate" with composite Product\Copier model
  * Replaced event "catalog_product_prepare_save" with controller product initialization helper that can be customozed via plugins
  * Consolidated Authorize.Net functionality in single module Authorizenet
  * Eliminated dependency of Sales module on Shipping and Usa modules
  * Eliminated dependency of Shipping module on Customer module
  * Improved accuracy and quality of Module Dependency Test
* Fixed bugs:
  * Fixed an issue when order was sent to PayPal in USD regardless of currency used during order creation
  * Fixed an issue with 404 error when clicking any button on a Recurring Billing Profile in the backend
  * Fixed an issue with synchronization with Google Shopping on product update caused by missed service property
  * Fixed ability to submit order in the backend when Authorize.Net Direct Post is used
  * Fixed an issue with notice that _attribute_set column is missing during Import/Export
* Removed the deprecated service-calls and data source functionality
* Request\Response workflow improvements:
  * Added Console\Response
  * Changed behavior of AppInterface to return ResponseInterface instead of sending it