Added CI_ Prefix to the Cache driver.
diff --git a/system/libraries/Cache/drivers/Cache_apc.php b/system/libraries/Cache/drivers/Cache_apc.php
index 4b995c7..de75719 100644
--- a/system/libraries/Cache/drivers/Cache_apc.php
+++ b/system/libraries/Cache/drivers/Cache_apc.php
@@ -25,7 +25,7 @@
  * @link		
  */
 
-class Cache_apc extends CI_Driver {
+class CI_Cache_apc extends CI_Driver {
 
 	/**
 	 * Get