Fixed a bug in plural() with words that end in y

http://codeigniter.com/bug_tracker/bug/6342/
diff --git a/system/helpers/inflector_helper.php b/system/helpers/inflector_helper.php
index 9393f11..39db5d4 100644
--- a/system/helpers/inflector_helper.php
+++ b/system/helpers/inflector_helper.php
@@ -87,7 +87,9 @@
 
 		if ($end == 'y')
 		{
-			$str = substr($str, 0, strlen($str)-1).'ies';
+			// Y preceded by vowel => regular plural
+			$vowels = array('a', 'e', 'i', 'o', 'u');
+			$str = in_array(substr($str, -2, 1), $vowels) ? $str.'s' : substr($str, 0, -1).'ies';
 		}
 		elseif ($end == 's')
 		{