Rest Auth Config Change

I updated the 'rest_auth' variable by setting it to lower case to prevent any auth errors if you use capitalized or uppercase letters in that config item. 

Reason for change was due to documentation and unexpected errors.

Author: jtrainaldi

application/libraries/REST_Controller.php

@@ -213,11 +213,11 @@ public function __construct()
 		// When there is no specific override for the current class/method, use the default auth value set in the config
 		if ($this->auth_override !== TRUE)
 		{
-			if ($this->config->item('rest_auth') == 'basic')
+			if (strtolower( $this->config->item('rest_auth') ) == 'basic')
 			{
 				$this->_prepare_basic_auth();
 			}
-			elseif ($this->config->item('rest_auth') == 'digest')
+			elseif (strtolower( $this->config->item('rest_auth') ) == 'digest')
 			{
 				$this->_prepare_digest_auth();
 			}
@@ -1227,11 +1227,11 @@ protected function _check_whitelist_auth()
 	 */
 	protected function _force_login($nonce = '')
 	{
-		if ($this->config->item('rest_auth') == 'basic')
+		if (strtolower( $this->config->item('rest_auth') ) == 'basic')
 		{
 			header('WWW-Authenticate: Basic realm="'.$this->config->item('rest_realm').'"');
 		}
-		elseif ($this->config->item('rest_auth') == 'digest')
+		elseif (strtolower( $this->config->item('rest_auth') ) == 'digest')
 		{
 			header('WWW-Authenticate: Digest realm="'.$this->config->item('rest_realm').'", qop="auth", nonce="'.$nonce.'", opaque="'.md5($this->config->item('rest_realm')).'"');
 		}