That looks like it is an error due to TinyMCE (editorremov I believe) not being loaded yet. Either hook to the admin_footer action instead of admin_head (interestingly you have declared the in_footer option as true and it is still not working) or declare the editorremov dependency when enqueuing your script:
wp_enqueue_script( 'features', plugin_dir_url( __FILE__ ) . 'features.js', array( 'editorremov' ), 'false', true );