docs fix
Scroller: mouse wheel only works inside content bounds (so that panel doesn't scroll when mouse wheel turns over header and footer) (closes #645)
LayoutGroup: clipContent works when width or height is zero (closes #644)
Scroller: clipRect width and height must be at least zero
TabBar: cleaned up selection handling (closes #635)
PopUpManager: centered pop-ups stay centered wwhen the stage resizes (closes #638)
Callout: backgroundSkin is not required (closes #626)
Text editors: better handling of scaling
StageText: better scaling
StageText: support for rotation
removed trace
TextFieldTextEditor: support for rotation (font must be embedded)