* Application initialization improvements:
  * Removed application initialization responsibility from `Mage` class
  * Introduces entry points, which are responsible for different types of requests processing: HTTP, media, cron, indexing, console installing, etc.
  * New configuration classes are introduced and each of them is responsible for specific section of configuration
  * Class rewrites functionality removed from `Mage_Core_Model_Config` model. DI configuration should be used for rewriting classes
* Added ability to configure object manager with array in addition to object and scalar values
* VDE improvements:
  * Theme CSS files viewing and uploading/downloading of custom CSS file
  * Updated styling of VDE Tools panel
* Refactored various components to an analogous jQuery widget:
  * Refactored components:
    * Category navigation
    * Products management and gallery
    * Send to friend
    * Sales components, including orders and returns
    * Retrieve shipping rates and add/remove coupon in shopping cart
    * Customer address and address book
    * Customer wishlist
    * "Contact Us" form
    * CAPTCHA
    * Weee
  * New tabs widget is used instead of `Varien.Tabs`
  * Refactored `Varien.dateRangeDate` and `Varien.FileElement`
  * Replaced `$.mage.constants` with jQuery UI `$.ui.keyCode` for keyboard key codes
* Refactored configurable attribute, category parent and attribute set selectors to use suggest widget
* Bug fixes:
  * Improvements and bug fixes in new backend theme
  * Image, categories attributes and virtual/downloadable fields are displayed on Update Attributes page, where they shouldn't be present
  * Undefined config property in `reloadOptionLabels()` function in `configurable.js` (Chrome)
  * Impossible to edit existing customer/product tax class
  * Incorrect format of customer's "Date of Birth"
  * Theme preview images are absent in VDE
  * Search by backslash doesn't work for Categories field on product creation page
  * Impossible to assign a category to a product, if category name contains HTML tag
  * Incorrect URL generated for logo image

* Implemented functional limitation that restricts max number of catalog products in the system
* Implemented cache backend library model for MongoDB
* Converted some more grids in backend from PHP implementation to declarations in layout
* Removed `app/etc/local.xml.additional` sample file, moved detailed description of possible configuration options to documentation
* Refactored `Mage_Core_Model_EntryPointAbstract` to emphasize method `processRequest()` as abstract
* Moved declaration of functional limitations to the nodes `limitations/store` and `limitations/admin_account`
* Bug fixes:
  * Fixed JavaScript and markup issues on product editing page in backend that caused erroneous sending of AJAX-queries and not rendering validation messages
  * Fixed issues of application initialization in cases when `var` directory doesn't have writable permissions. Writable directories are validated at an early stage of initialization
  * Fixed array sorting issues in test `Magento_Filesystem_Adapter_LocalTest::testGetNestedKeys()` that caused occasional failures