Delete dimension entries from shopp_meta on product deletion

In table shopp_meta, dimensions are stored with a relation to table shopp_price on shopp_meta.parent = shopp_price.id. 

Right now these entries in meta are left behind after deleting a product. Because of the mentioned relation the removal of the entries needs to be done before removal of shopp_price entries.
Typo in code
Fixed #2536

Exclude products in one or more specified collections from storefront, by collection-id.
shopp('storefront.catalog-products','exclude=3,8,12');

Products that have multiple collections attached, will still show if one of the attached collections is not in specified in 'exclude'-option.
Products in 'Uncategorized' will not show.
Merge pull request #2883 from Just-m/1.3.x

Delete dimension entries from shopp_meta on product deletion, add category exclude options to smart collections