[+FEATURE] FLOW3 (MVC): Enable bulk assignment of template variables in AbstractView. Just call $this->view->assignMultiple(array('key1' => 'value1', 'key2' => 'value2')) to set multiple keys at once. Resolves #3997
[+BUGFIX] FLOW3 (MVC): AbstractView::assign() now returns itself as stated in the comment. This enables method chaining like: $this->view->assign('key1', 'value1')->assign('key2', 'value2');
[+TASK]: FLOW3 (MVC): Tweaked NotFoundView and StandardView and added test cases for all views of the FLOW3 MVC Subpackage.
[-TASK]: Fluid (View): Removed obsolete Method assign() from TemplateView as this method already exists in the parent class. The check for the key "view" is not needed anymore since the view is stored in the VariableContainer