1. Various bug fixes provided by ognjen.kuljic, thanks for the help!
2. Add the content by replacing the shortcode, not the whole page content.
 That allows you to add text before and after the shop output.

git-svn-id: https://plugins.svn.wordpress.org/orillacart/trunk@852296 b8457f37-d9ea-0310-8a92-e5e31aec5664