2.0.0.0-dev49

* Various improvements:
  * Unified Area configuration
  * Moved EventManager to Magento\Event lib component
  * Moved FrontController, Routers, Base Actions to Magento\App
  * Created Magento\App component in library
  * Declared public interfaces for View component into library
  * Plushe theme is set as the default theme
  * Refactor the Blacklist Pattern in the Integrity Test Suite's ClassesTest to Replace Blacklist.php Files
  * Removed JavaScript unit test TreeSuggestTest.prototype.testBind as obsolete
  * Introduced ability to register a template engine to process template files having certain extension
  * Removed support of the Twig template engine along with the corresponding component from the library
  * Removed layout flag that forced template blocks to output rendered content directly to a browser bypassing the response object
  * Moved out responsibility of rendering template debugging hints from the template block to the plugin and decorator for a template engine
* Fixed bugs:
  * Fixed inability to create product if multiple attributes are assigned to attribute set
  * Fixed inability to create a new widget instance
  * Fixed error on Customers Segments Conditions tab while the 'Number of Orders' condition is chosen
  * Fixed blank page when placing order via Ogone
  * Fixed various UI issues in Admin Panel with layout, aligning, buttons and fields
  * Fixed static tests failing to verify themes files