Added "dovetail_skip_content_check" filter, which allows theme developers to skip authorisation checks in certain page templates if they want to (e.g. add "add_filter( "dovetail_skip_content_check", '__return_true', 10 );" at the top of the template to skip the auth check)

git-svn-id: https://plugins.svn.wordpress.org/dovetail/trunk@885664 b8457f37-d9ea-0310-8a92-e5e31aec5664