Input class: change behavior of get_post() method, add post_get() method

followup to PR #2522
diff --git a/user_guide_src/source/changelog.rst b/user_guide_src/source/changelog.rst
index 4a45a71..ba104bb 100644
--- a/user_guide_src/source/changelog.rst
+++ b/user_guide_src/source/changelog.rst
@@ -388,6 +388,7 @@
       -  Changed method ``valid_ip()`` to use PHP's native ``filter_var()`` function.
       -  Changed internal method ``_sanitize_globals()`` to skip enforcing reversal of *register_globals* in PHP 5.4+, where this functionality no longer exists.
       -  Changed methods ``get()``, ``post()``, ``get_post()``, ``cookie()``, ``server()``, ``user_agent()`` to return NULL instead of FALSE when no value is found.
+	  -  Changed method ``get_post()`` to check in GET then in POST. Added method ``post_get()`` which checks in POST then in GET, as ``get_post()`` was doing before.
       -  Changed method ``_fetch_from_array()`` to parse array notation in field name.
 
    -  :doc:`Common functions <general/common_functions>` changes include: