changelog updates for Rails 4 [ci skip]

actionmailer/CHANGELOG.md

 ## Rails 4.0.0 (unreleased) ##
 
-*   No changes
+*   Upgrade mail version to 2.4.3 *ML*
 
 
 ## Rails 3.2.1 (January 26, 2012) ##

actionpack/CHANGELOG.md

 ## Rails 4.0.0 (unreleased) ##
 
+* Upgrade rack-cache to 1.2. *José Valim*
+
+* ActionController::SessionManagement is removed. *Santiago Pastorino*
+
+* Since the router holds references to many parts of the system like engines, controllers and the application itself, inspecting the route set can actually be really slow, therefore we default alias inspect to to_s. *José Valim* 
+
+* Add a new line after the textarea opening tag. Closes #393 *rafaelfranca*
+
+* Always pass a respond block from to responder. We should let the responder to decide what to do with the given overridden response block, and not short circuit it. *sikachu*
+
+* Fixes layout rendering regression from 3.2.2. *José Valim*
+
 * Adds support for layouts when rendering a partial with a given collection. *serabe*
 
 * Allows the route helper `root` to take a string argument. For example, `root 'pages#main'`. *bcardarella*

activemodel/CHANGELOG.md

+## Rails 4.0.0 (unreleased) ##
+
 *   Added ActiveModel::Model, a mixin to make Ruby objects work with AP out of box *Guillermo Iguaran*
 
 *   `AM::Errors#to_json`: support `:full_messages` parameter *Bogdan Gusiev*

activerecord/CHANGELOG.md

 ## Rails 4.0.0 (unreleased) ##
 
+*   Whitelist all attribute assignment by default. Change the default for newly generated applications to whitelist all attribute assignment.  Also update the generated model classes so users are reminded of the importance of attr_accessible. *NZKoz*
+
+*   Update ActiveRecord::AttributeMethods#attribute_present? to return false for empty strings. *Jacobkg*
+
+*   Fix associations when using per class databases. *larskanis*
+
+*   Revert setting NOT NULL constraints in add_timestamps *fxn*
+
+*   Fix mysql to use proper text types. Fixes #3931. *kennyj*
+
+*   Fix #5069 - Protect foreign key from mass assignment through association builder. *byroot*
+
 *   Added the schema cache dump feature.
 
     `Schema cache dump` feature was implemetend. This feature can dump/load internal state of `SchemaCache` instance