Fixes bug where product reports itself as in the cart when it's not
Filter out ancestors from product category CMS selection box.
Ancestor categories are automatically included in search results etc, so theres no point in specifying them as additional categories.
Tidied the Product.php class to conform to coding style conventions
Removed unused functions: Order->checkoutLink() and Product->getCart()
Removed unused link functions from Product.php
Migrate product_versions BasePrice
Merge pull request #244 from nimeso/patch-16

Migrate product_versions BasePrice
Removed Order->updatePaymentStatus function that was made obsolete by OrderProcessor->completePayment()
Added set MemberID on order in OrderProcessor (if not already set). This helps to ensure member is set, when a member is logged in.
Removed unneeded code from ShoppingCart + tidy.
Reverting 01be35fb901d7e23344ef5ffa10aa3729ac7e18e, as the add/remove product functions were actually needed.
Updated CartPage.ss to work with changes in 2aed586260b9dfc67b6e1bfaf47cf544cde56796
README url fix
Updated model admin menu priorities so admin sections sit more logically.
Minor tidy of Order and ShopTest
Rearranged some functions and code in OrderProcessor
FIX: Offsite payments were preventing order from being viewed.
Fixed by 'archiving' shopping cart session id to order manipulation historical order ids.
Fixes #246
Make sure billing address is set, even if it isn't entered.
Fixes #247
Added hack to allow overriding Address required_fields
Refactored Order->calculate() into it's own OrderTotalCalculator class.
Some other general tidy in Order
Further clean and tidy of Order