[VisUI Request] Set text orientation in VisImageTextButton

[bploeckelman]

It would be helpful to have something like a textAlignment property in VisImageTextButton that positions the text label relative to the image in the button table.

Defaulting the value to right would match the existing behavior but if it's set to top or bottom the label would be placed on a separate row above or below the image, and if it's set to left then the label would be added to the button table first, followed by the image.

[czyzby]

Thanks for implementing this feature, @bploeckelman!