Updated Readme

git-svn-id: https://plugins.svn.wordpress.org/multicolumn-category-widget/trunk@910989 b8457f37-d9ea-0310-8a92-e5e31aec5664
Typo

git-svn-id: https://plugins.svn.wordpress.org/multicolumn-category-widget/trunk@910993 b8457f37-d9ea-0310-8a92-e5e31aec5664