Add scaleGrid support to Group
Group now has basic scaleGrid support.
- The group can not have any displayObject child elements. This includes GraphicElements that require their own displayObject.
- Every scaleGrid property must be set. If they aren't, then the scale9Grid is not set.
- Every scaleGrid property must be valid. All values must fit in the dimensions of the Group.
- ResizeMode is automatically set to scale
- Change the width and height of the Group to scale the dimensions. ScaleX and scaleY will be ignored.
QE Notes: Add scaleGrid tests for Group
Doc Notes: Need to document the scaleGrid properties