CI_Utf8-related changes

 - Give priority to mb_convert_encoding() over iconv() in clean_string() (partially fixes #261)
 - Add more proper unit tests
diff --git a/user_guide_src/source/changelog.rst b/user_guide_src/source/changelog.rst
index a3e7980..0a6bd76 100644
--- a/user_guide_src/source/changelog.rst
+++ b/user_guide_src/source/changelog.rst
@@ -507,7 +507,7 @@
    -  UTF-8 Library changes include:
 
       -  ``UTF8_ENABLED`` now requires only one of `Multibyte String <http://php.net/mbstring>`_ or `iconv <http://php.net/iconv>`_ to be available instead of both.
-      -  Changed method ``clean_string()`` to utilize ``mb_convert_encoding()`` if it is available but ``iconv()`` is not.
+      -  Changed method ``clean_string()`` to utilize ``mb_convert_encoding()`` if it is available.
       -  Renamed method ``_is_ascii()`` to ``is_ascii()`` and made it public.
 
    -  Added `compatibility layers <general/compatibility_functions>` for:
@@ -721,6 +721,7 @@
 -  Fixed a bug (#43) :doc:`Image Manipulation Library <libraries/image_lib>` method ``text_watermark()`` didn't properly determine watermark placement.
 -  Fixed a bug where :doc:`HTML Table Library <libraries/table>` ignored its *auto_heading* setting if headings were not already set.
 -  Fixed a bug (#2364) - :doc:`Pagination Library <libraries/pagination>` appended the query string (if used) multiple times when there are successive calls to ``create_links()`` with no ``initialize()`` in between them.
+-  Partially fixed a bug (#261) - UTF-8 class method ``clean_string()`` generating log messages and/or not producing the desired result due to an upstream bug in iconv.
 
 Version 2.1.4
 =============