Added a dynamic layout system where UI elements can be moved about on a tiled grid.

components/layout_item.tscn

@@ -0,0 +1,12 @@
+[gd_scene format=3]
+
+[ext_resource type="Script" path="res://scripts/layout_item.gd" id="1"]
+
+[node name="LayoutItem" type="Control"]
+layout_mode = 0
+script = ExtResource("1")
+
+[node name="Background" type="Panel" parent="."]
+layout_mode = 0
+mouse_filter = 2
+theme_type_variation = &"LayoutItemBackground"