Update arrangement logic for containers, remove position property from Rect, add Size property to IElement.

Voile/Source/UI/IElement.cs

@@ -7,6 +7,7 @@ namespace Voile.UI;
 public interface IElement
 {
     public Vector2 Position { get; set; }
+    public Rect Size { get; set; }
 }
 
 public interface IParentableElement
@@ -15,6 +16,14 @@ public interface IParentableElement
     public void AddChild(IElement child);
 }
 
+public interface IResizeableElement
+{
+    /// <summary>
+    /// Get a minimum rectangle size for this element.
+    /// </summary>
+    public abstract Rect MinimumRect { get; }
+}
+
 public interface IUpdatableElement
 {
     void Update();