CI_Upload changes

- Method chaining support.
- A more abstract resetting of the default settings.
- Added an option to initialize() to disable resetting to default settings.
- Removed method mimes_types() and slightly optimized chunks of code where it was used.
- Added the ability to pass allowed_types as an array.
diff --git a/user_guide_src/source/libraries/file_uploading.rst b/user_guide_src/source/libraries/file_uploading.rst
index d7ba3a6..d93acb8 100644
--- a/user_guide_src/source/libraries/file_uploading.rst
+++ b/user_guide_src/source/libraries/file_uploading.rst
@@ -201,7 +201,7 @@
                                                                        directory must be writable and the path can be absolute or relative.
 **allowed_types**            None              None                    The mime types corresponding to the types of files you allow to be
                                                                        uploaded. Usually the file extension can be used as the mime type.
-                                                                       Separate multiple types with a pipe.
+                                                                       Can be either an array or a pipe-separated string.
 **file_name**                None              Desired file name       If set CodeIgniter will rename the uploaded file to this name. The
                                                                        extension provided in the file name must also be an allowed file type.
                                                                        If no extension is provided in the original file_name will be used.
@@ -254,6 +254,13 @@
 
 .. class:: CI_Upload
 
+	.. method:: initialize([array $config = array()[, $reset = TRUE]])
+
+		:param	array	$config: Preferences
+		:param	bool	$reset: Whether to reset preferences (that are not provided in $config) to their defaults
+		:returns:	CI_Upload instance (method chaining)
+		:rtype:	CI_Upload
+
 	.. method:: do_upload([$field = 'userfile'])
 
 		:param	string	$field: Name of the form field