Implement Query Product Variant [sphere.io] according to documentation. Fixes #733
Merge pull request #31 from elasticio/733-query_product_variant_artem

Implement Query Product Variant [sphere.io] according to documentation. ...
Implement addPrice [sphere.io] action. Fixes #734
Merge pull request #34 from elasticio/734-add_price_artem

Implement addPrice [sphere.io] action. Fixes #734
Merged with node_refactoring