Add setting ['composer_autoload']

Supersedes PR #3132
diff --git a/application/config/config.php b/application/config/config.php
index d269b6e..b6b3c9f 100644
--- a/application/config/config.php
+++ b/application/config/config.php
@@ -121,7 +121,6 @@
 */
 $config['enable_hooks'] = FALSE;
 
-
 /*
 |--------------------------------------------------------------------------
 | Class Extension Prefix
@@ -136,6 +135,27 @@
 */
 $config['subclass_prefix'] = 'MY_';
 
+/*
+|--------------------------------------------------------------------------
+| Composer auto-loading
+|--------------------------------------------------------------------------
+|
+| Enabling this setting will tell CodeIgniter to look for a Composer
+| package auto-loader script in application/vendor/autoload.php.
+|
+|	$config['composer_autoload'] = TRUE;
+|
+| Or if you have your vendor/ directory located somewhere else, you
+| can opt to set a specific path as well:
+|
+|	$config['composer_autoload'] = '/path/to/vendor/autoload.php';
+|
+| For more information about Composer, please visit http://getcomposer.org/
+|
+| Note: This will NOT disable or override the CodeIgniter-specific
+|	autoloading (application/config/autoload.php)
+*/
+$config['composer_autoload'] = FALSE;
 
 /*
 |--------------------------------------------------------------------------