Spelling fixes - `wether` to `whether`

Interestingly `wether` means a castrated ram in old English
diff --git a/system/core/Hooks.php b/system/core/Hooks.php
index 29fd882..afbf4b4 100644
--- a/system/core/Hooks.php
+++ b/system/core/Hooks.php
@@ -39,7 +39,7 @@
 class CI_Hooks {
 
 	/**
-	 * Determines wether hooks are enabled
+	 * Determines whether hooks are enabled
 	 *
 	 * @var bool
 	 */
@@ -53,7 +53,7 @@
 	public $hooks =	array();
 
 	/**
-	 * Determines wether hook is in progress, used to prevent infinte loops
+	 * Determines whether hook is in progress, used to prevent infinte loops
 	 *
 	 * @var bool
 	 */