Updating the readme.

git-svn-id: https://plugins.svn.wordpress.org/custom-pointers/trunk@893325 b8457f37-d9ea-0310-8a92-e5e31aec5664
Trying to get screenshots to appear in the WP Plugin Directory page.

git-svn-id: https://plugins.svn.wordpress.org/custom-pointers/trunk@893328 b8457f37-d9ea-0310-8a92-e5e31aec5664