title: Add "Select All" to Post Categories. Option to add new post to all categories in a custom taxonomy?
body: <p>I have a custom taxonomy of US states for a custom post type. Currently when adding a new post to this custom post type I have to manually check all 50 states (if applicable) is there a way to add a button inside of the custom taxonomy metabox that when pressed would check all of the boxes to assign the post to all 50 states?</p>