* Improved Themes functionality to meet the following requirements:
  * Magento instance doesn’t crash in case there’re no themes at all
  * Features like selection of themes in system configuration, custom theme selection in Custom Design, CMS pages, Products and Categories can work without themes. They use base view files only.
  * Virtual themes work in the same way as the non-virtual (which are present in file system) though they additionally have inheritance property. Changes were made in theme switcher, in fallback mechanism, in widgets etc.
  * Non-virtual themes are being added to DB during installation
  * Application framework uses theme id as identifier instead of theme code
* Refactored a variety of report grids in backend (admin) to make them configurable through layout, rather than hard-coded.
* Removed obsolete modules:
  * `Mage_XmlConnect`
  * `Mage_Dataflow`
* Significantly changed Logging subsystem:
  * `Mage_Core_Model_Logger` class is responsible for logging
  * Changes are made to comply with DI paradigm
  * Custom logger in `Mage_Backend_Menu` subsystem is removed due to usage of regular one
* Changes made in autoload process
  * Fixed autoload to prevent `class_exists()` from causing fatal error
  * The `Magento_Autoload` library was divided into 2 classes: `Magento_Autoload_IncludePath` is responsible for loading from include path, `Magento_Autoload_ClassMap` from a class map. Stacked "class map" loader on top of "include path" loader in application bootstrap.
* Implemented new jQuery form widget. Its responsibility is to prepare form for submission (change form attributes if needed)
  * Replaced usage of different instances of `varienForm` with a new form widget (`productForm`, `categoryForm`, instances of type "onclick declaration", "as child component", "instantiation only")
  * Replaced prototype validation with jQuery analog
  * Additionally implemented form widget in different modules (CMS, Customer, Backend, Sitemap, DesignEditor, Tags, SystemEmail, Newsletters, ImportExport, Connect, Authorize.net)
* Minor improvements
  * Fixed css styles for validation messages in different parts of the system
  * Removed usage of `jquery-ui-1.8.21.custom.css`
  * Updated versions of jQuery and jQuery-UI on backend
  * Updated Magento trademark and copyright labels at the bottom of pages: changed legal entity name to X.Commerce, Inc, made translation engine pick them up
  * Improvements made in indexers to stabilize tests. Fixed wrong initialization order of indexers that sometimes caused failure of reindexing all at once
* Bugfixes:
  * Set correct order's data change state during voiding the order
  * Set translator to pick up status labels in drop-down in "Shopping cart price rule" admin grid
  * Fixed an issue in console installer that initialized application in such a way, that it could not load certain event area.
  * Fixed incorrect loader image source in backend during new tax rule creation
  * Fixed JS error in IE with creating products via floating toolbar
  * Fixed image save url during uploading product's images
  * Added permission check for editing shipping and billing addresses during viewing the order
  * Changed saving of order comments from backend. Comment is saved even without status change
  * Added additional validation into `quickCreateAction` of `Mage_Adminhtml_Catalog_ProductController` to prevent saving new product with any id using firebug
  * Fixed JS errors in Authorize.net Direct Post submodule
  * Fixed JS errors in split button on creating product
  * Fixed errors in poll's list template in backend