* Added 'width' and 'height' properties to Group. For now, they are readonly and are only respected for layout='split', but eventually they should be overridable and respected by all the layout options in Traits. 
* Added 'width' and 'height' properties to Group. For now, they are readonly and are only respected for layout='split', but eventually they should be overridable and respected by all the layout options in Traits. 


burnpanck/traits,burnpanck/traits