* Fixes#1557. Ensures the border child not to be null.
* Improves the PanelView and some bug fixes.
* Implementing rounded corners border.
* Fixes some items not showing on page down/up.
* Allowing pass the view to the RootMouseEvent.
* Allowing bring the current window to front on dragging.
* Improving the ConsoleDriver to get the Attribute colors based on the value.
* Added a PanelView to deal with borders.
* Added a Border feature to all views.