2.0.0.0-dev75

* Modularity improvements:
  * Introduced a new CheckoutAgreements module. Moved all "Terms and Conditions" related logic from Magento_Checkout to Magento_CheckoutAgreements
  * Moved library related logic from `Magento\Core\Model\App`
* Fixed bugs:
  * Fixed an issue where Currency Options were not displayed on the Currency Setup tab
  * Fixed an issue where a fatal error appeared during customer registration if mail server was off
  * Fixed an issue where customer with middle name did not appear in the Customers grid in the backend
  * Fixed an issue where related products were not displayed on the product page in the backend
  * Fixed the broken View Files Population tool
  * Fixed an issue where Magento broke down if the Main Web Site was deleted
  * Fixed potential security issue with orders protect_code
  * Fixed an issue where an error appeared when placing an order if cache was turned on
  * Fixed an issue where a warning appeared when running system_config.php tool
  * Fixed an issue with incorrect reset password link for users on custom websites
  * Fixed an issue with invalid error message displayed when trying to save a customer group with existing group name
  * Fixed an issue with  menu layout non-responsive behavior  in the Blank theme
* Framework Improvements:
  * Covered Magento library components with unit tests
    * `Magento\Framework\Error\*`
    * `Magento\Framework\Event\Observer\*`
    * `Magento\Framework\Filesystem\*`
    * `Magento\Framework\Filesystem\File\*`
  * Updated the obsolete_classes list with changes, introduced by Offline Payment Methods Module implementation
  * Moved `lib/Magento/*` to `lib/Magento/Framework/*`
  * Covered Magento application components with unit tests:
     * `Store\Model\*`
     * `Sales/Helper/Guest.php`
     * `Sales/Helper/Admin.php`
     * `Sales/Model/Observer.php`
     * `Sales/Model/Payment/Method/Converter.php`
     * `Sales/Model/Email/Template.php`
     * `Sales/Model/Observer/Backend/CustomerQuote.php`
     * `Sales/Model/Status/ListStatus.php`
* Refactored the following modules to use Customer Service:
  * Magento_Persistent
  * Magento_GoogleShopping
  * Magento_ProductAlert
  * Magento_SendFriend
  * Moved customer-specific logic from the Magento_ImportExport module to the Customer module
  * Refactored the rest of Customer Group usages
  * Refactored customerAccountService::createAccount to not expose the hashed password input from webapi
  * Implemented a delimiter usage for Cache key in Customer Registry
* Customer Service usage:
  * Updated exception hierarchy with a new localized exception class
  * Updated CRUD APIs to support email and base URL instead of IDs
* JavaScript improvements:
  * Implemented the validation widget
  * Implemented the tooltip widget
  * Implemented the popup/modal window widget
  * Implemented the calendar widget
  * Implemented the suggest widget
* Added configuration for Travis CI