Added a "toggle all menus for the selected role" button for the Pro version. 

The "check-all.png" icon comes from the spirit20 icon collection and is licensed under GPL. More information: http://19eighty7.com/icons

git-svn-id: https://plugins.svn.wordpress.org/admin-menu-editor/trunk@772163 b8457f37-d9ea-0310-8a92-e5e31aec5664