Righting a wrong in the Session library

 - Change userdata(), flashdata(), tempdata() to return all the respective data when no parameter is passed.
 - Revert the addition of all_flashdata().
 - Deprecate all_userdata().
 - Fix related changelog entries that were all inconsistent.
diff --git a/user_guide_src/source/libraries/sessions.rst b/user_guide_src/source/libraries/sessions.rst
index 2f8bea0..3368a9f 100644
--- a/user_guide_src/source/libraries/sessions.rst
+++ b/user_guide_src/source/libraries/sessions.rst
@@ -137,7 +137,7 @@
 
 An array of all userdata can be retrieved as follows::
 
-	$this->session->all_userdata()
+	$this->session->userdata()
 
 And returns an associative array like the following::
 
@@ -194,7 +194,7 @@
 
 An array of all flashdata can be retrieved as follows::
 
-	$this->session->all_flashdata();
+	$this->session->flashdata();
 
 
 If you find that you need to preserve a flashdata variable through an