Fix Panel and Window header styling.
Make Overlay an abstract class, and remove its `autoDestroy` config. Will re-implement that in a concrete Overlay subclass (probably PopOverOverlay, when it's re-implemented).
Implement the close button, and closing on 'esc' key press for Window.
Change ToolButton's `ttype` config to `toolType`, and fix styling.
Fix some ToolButton styling.
Fix to form Field styling to allow td elements to have overridden padding.