Bug fix for the is installed check.


git-svn-id: https://plugins.svn.wordpress.org/share-link/trunk@1004894 b8457f37-d9ea-0310-8a92-e5e31aec5664
Updated readme for new version.


git-svn-id: https://plugins.svn.wordpress.org/share-link/trunk@1004895 b8457f37-d9ea-0310-8a92-e5e31aec5664