updated plugin to support latest version of Jigoshop and Basket Support to send cart details to SagePay.

git-svn-id: https://plugins.svn.wordpress.org/sagepay-server-gateway-for-jigoshop/trunk@1008550 b8457f37-d9ea-0310-8a92-e5e31aec5664
cleaned the code.

git-svn-id: https://plugins.svn.wordpress.org/sagepay-server-gateway-for-jigoshop/trunk@1008553 b8457f37-d9ea-0310-8a92-e5e31aec5664