Implements tests for basket attribute client in catalog detail view
Removes unused code in basket client of catalog detail view
Minor improvements when inserting product list test data
Implements selection client in catalog detail view for product variants
Additionally, fixes a problem in the basket controller with incomplete and non-unique variant attributes when checking selection products
Adapts the unit test data and the dependent tests in the catalog index manager tests
Extends ProductPrice plugin to handle selection products correctly
Important: The order product ID is now the ID of the parent product of a selection while the product code is still the code of the article
Revert "Extends ProductPrice plugin to handle selection products correctly"

This reverts commit 43d57f7c16bef2a669b3dfdd3dbad695032772db.
Revert "Implements selection client in catalog detail view for product variants"

This reverts commit 9d6dffadb5c6f7d29d3f70bc641ed9b05fc8c9c3.
Merge pull request #251 from nsendetzky/master

Improves tests and code for basket part in catalog detail view