Added option to choose displayed categories in Showcase box.
Added option to choose displayed categories in Showcase box.

diversantvlz/WellCommerce,WellCommerce/AppBundle,WellCommerce/OrderBundle,WellCommerce/CouponBundle,WellCommerce/CatalogBundle,WellCommerce/AppBundle,WellCommerce/wellcommerce-default-theme,WellCommerce/CoreBundle,WellCommerce/WishlistBundle,WellCommerce/CoreBundle,diversantvlz/WellCommerce,WellCommerce/CmsBundle,diversantvlz/WellCommerce,WellCommerce/CouponBundle,WellCommerce/WellCommerce,WellCommerce/WellCommerce,WellCommerce/OAuthBundle,WellCommerce/wellcommerce-default-theme,WellCommerce/CatalogBundle,WellCommerce/SearchBundle,WellCommerce/ReviewBundle,WellCommerce/AppBundle,WellCommerce/WellCommerce,WellCommerce/OrderBundle,WellCommerce/CmsBundle,WellCommerce/ReviewBundle