Fix typo in comments
diff --git a/system/core/Common.php b/system/core/Common.php
index ce324a1..ad3ca9f 100644
--- a/system/core/Common.php
+++ b/system/core/Common.php
@@ -677,7 +677,7 @@
 	 * of CodeIgniter.php. The main reason we use this is to simulate
 	 * a complete custom exception handler.
 	 *
-	 * E_STRICT is purposivly neglected because such events may have
+	 * E_STRICT is purposively neglected because such events may have
 	 * been caught. Duplication or none? None is preferred for now.
 	 *
 	 * @link	http://insomanic.me.uk/post/229851073/php-trick-catching-fatal-errors-e-error-with-a