Implement skip-parameter
Implemented exclusion of subcategories, useful alternative to http://wordpress.org/support/topic/is-it-possible-to-get-sub-category-post-nested

git-svn-id: https://plugins.svn.wordpress.org/category-posts-in-custom-menu/trunk@961235 b8457f37-d9ea-0310-8a92-e5e31aec5664