Right align
How can I right-align three buttons?
This does not work:

```nim
import nigui
app.init()
var window = newWindow()
var container = newLayoutContainer(Layout_Horizontal)
container.widthMode = WidthMode_Expand
container.xAlign = XAlign_Right
window.add(container)
for i in 1..3:
  var control = newButton("Button " & $i)
  container.add(control)
window.show()
app.run()
```