Update readme text

git-svn-id: https://plugins.svn.wordpress.org/spiffy-calendar/trunk@918648 b8457f37-d9ea-0310-8a92-e5e31aec5664
Update readme text

git-svn-id: https://plugins.svn.wordpress.org/spiffy-calendar/trunk@918650 b8457f37-d9ea-0310-8a92-e5e31aec5664