Empty cache when setting payment and shipping methods
Use method to check if shipping or payment is required
Addresses (in tl_iso_addresses) can now belong to multiple parent tables
Added some helper methods to the Address model
Use model to access address data
Product collection should store address data in tl_iso_addresses

Added dynamic ptable and adjusted database fields.
Added get/set billing and shipping address methods to ProductCollection
Use Address model everywhere
Use model to generate address info in the backend
CS, comments, static methods
Address model can be used to create address enriched with member data
Do not run getRelated if address ID is 0 or empty
Cart collection will return member data if no address is set
Address model can return null
Show addresses again in collection table
Merge branch 'feature/address-subtable' into develop
Added helper methods to OrderStatus model
Fixed incorrect foreignKey to tl_collection table
Use Order::updateOrderStatus() to trigger email etc
Use Model::getRelated() to find OrderStatus for a Collection