unify main scene for mobile

src/Main.gd

@@ -1,8 +1,10 @@
 extends Control
 
-onready var taquin = $HSplitContainer/Taquin
+onready var container = $GridContainer
+onready var taquin = $GridContainer/Taquin
 
 func _ready():
+	layout_reflow()
 	load_game()
 	print("Starting state: ", taquin.current_state_name())
 
@@ -11,6 +13,17 @@ func _notification(what):
 		save_game()
 		get_tree().quit() # default behavior
 
+func layout_reflow():
+	if container == null:
+		return
+
+	if container.rect_size.x < container.rect_size.y:
+		# portrait
+		container.columns = 1
+	else:
+		# landscape
+		container.columns = 2
+
 # https://docs.godotengine.org/en/3.2/tutorials/io/saving_games.html
 func save_game():
 	var save_game = File.new()