updated README

git-svn-id: https://plugins.svn.wordpress.org/wp-asset-manager/trunk@893569 b8457f37-d9ea-0310-8a92-e5e31aec5664
tagged 1.0.6

git-svn-id: https://plugins.svn.wordpress.org/wp-asset-manager/trunk@893570 b8457f37-d9ea-0310-8a92-e5e31aec5664