Update readme

git-svn-id: https://plugins.svn.wordpress.org/photocart-link/trunk@1028343 b8457f37-d9ea-0310-8a92-e5e31aec5664
New readme

git-svn-id: https://plugins.svn.wordpress.org/photocart-link/trunk@1028345 b8457f37-d9ea-0310-8a92-e5e31aec5664