don't show Glow
handle WindowStyle == WindowStyle.None

- no title bar
- no window commands
- no min, max, close
- resize is allowed
introduce UseNoneWindowStyle

because the BorderlessWindowBehavior set the WindowStyle to None !!!
minor documentation
HandleMaximize fix
fix of HandleMaximize fix
Merge pull request #779 from MahApps/717-punker76-windowstyle-none-blubb-blubb

allow metrowindow to set windowstyle none...