Force a single (2, 3, 4) column layout in WordPress 3.8

gistfile1.php

function jmo_screen_layout_columns($columns) {
	$columns['dashboard'] = 2;
	
	return $columns;
}

add_filter('screen_layout_columns', 'jmo_screen_layout_columns');

function jmo_screen_layout_dashboard() { 
	return 2; 
}

add_filter('get_user_option_screen_layout_dashboard', 'jmo_screen_layout_dashboard');