Change and Allow other mime types on upload

Mime-Types.php

<?php
/**
 * Plugin Name: Mime Types
 * Description: Allow other mime types on upload
 * Plugin URI:  
 * Version:     1.0.0
 * Author:      Frank Bültge
 * Author URI:  http://bueltge.de
 * License:     GPLv2
 * License URI: ./assets/license.txt
 * Text Domain: mime-types
 * Domain Path: /languages
 */

! defined( 'ABSPATH' ) && exit;

add_filter( 'upload_mimes', 'fb_custom_upload_mimes' );
/**
 * Change default mime types
 * 
 * @see     wp-includes/functions.php  wp_check_filetype_and_ext(), wp_get_mime_types()
 * 
 * @param   Array with existing Mime Types
 * @return  Array
 */
function custom_upload_mimes ( $mimes = array() ) {
	
	// add new extension to the array
	$mimes[ 'swf' ] = 'application/x-shockwave-flash';
	$mimes[ 'doc' ] = 'application/msword';
	$mimes[ 'pdf' ] = 'application/pdf';
	$mimes[ 'ppt' ] = 'application/powerpoint';
	
	// removing existing file types
	unset( $mimes[ 'exe' ] );
	
	return $mimes;
}