Adding readme.txt

git-svn-id: https://plugins.svn.wordpress.org/megamenu/trunk@943109 b8457f37-d9ea-0310-8a92-e5e31aec5664
Fix readme.txt

git-svn-id: https://plugins.svn.wordpress.org/megamenu/trunk@943110 b8457f37-d9ea-0310-8a92-e5e31aec5664