Remove assets directory

git-svn-id: https://plugins.svn.wordpress.org/admin-category-filter/trunk@844972 b8457f37-d9ea-0310-8a92-e5e31aec5664
Update readme

git-svn-id: https://plugins.svn.wordpress.org/admin-category-filter/trunk@844973 b8457f37-d9ea-0310-8a92-e5e31aec5664
Remove line break on description

git-svn-id: https://plugins.svn.wordpress.org/admin-category-filter/trunk@844974 b8457f37-d9ea-0310-8a92-e5e31aec5664