ContainerBox can now be aligned as well

object.go

@@ -155,6 +155,7 @@ type ContentBox interface {
 	ContentBounds         () image.Rectangle
 	ScrollTo              (image.Point)
 	OnContentBoundsChange (func ()) event.Cookie
+	SetAlign              (x, y Align)
 }
 
 // TextBox is a box that contains text content.
@@ -165,8 +166,6 @@ type TextBox interface {
 	SetTextColor (color.Color)
 	SetFace      (font.Face)
 	SetWrap      (bool)
-	SetHAlign    (Align)
-	SetVAlign    (Align)
 }
 
 // ContentBox is a box that can contain child objects. It arranges them
@@ -188,6 +187,8 @@ type LayoutHints struct {
 	Bounds image.Rectangle
 	OverflowX bool
 	OverflowY bool
+	AlignX    Align
+	AlignY    Align
 	Gap image.Point
 }