Fixes #17 by calling DismissPopupEvent synchronous
Fixes #13 by not setting IsOpen to false when the template is change but hiding and showing the backstage instead (we have to destroy the adorner)
Fixes #18 by making the ContentPresenter of RibbonWindow hittest visible in the window chrome
Code style (spaces)
Changelog for potential new version
Fixes #11 by removing unnecessary space at bottom and right side
Updating changelog