New Anchored constructor for top stage panes

src/main/scala/org/gerweck/scalafx/util/layout/Anchored.scala

@@ -0,0 +1,24 @@
+package org.gerweck.scalafx.util.layout
+
+import scalafx.geometry.Insets
+import scalafx.scene.control.MenuBar
+import scalafx.scene.layout._
+
+/** A wrapper that binds its child pane to all four corners so it will always
+  * grow as the stage is resized.
+  *
+  * This can be useful as the very top element of a [[scalafx.stage.Stage]]
+  *
+  * @author Sarah Gerweck <sarah.a180@gmail.com>
+  */
+object Anchored {
+  def apply(margins: Insets = Insets.Empty, menus: Option[MenuBar] = None)(body: => Pane) = {
+    new AnchorPane { ap =>
+      hgrow = Priority.Always
+      vgrow = Priority.Always
+      private[this] lazy val innerPane = body
+      children = menus.toSeq :+ innerPane
+      AnchorPane.setAnchors(innerPane, margins.top, margins.right, margins.bottom, margins.left)
+    }
+  }
+}