Make ESCLocation is_start_location work (#421)

Introducing BYPASS_LAST_ROOM global to allow changing scene without considering the previous room
Fixes godot-escoria/escoria-issues#40

game/rooms/room12/esc/room12.esc

@@ -11,9 +11,6 @@
 	# Set player look left
 	set_angle player 270
 	stop
-> [!last_scene]
-	teleport player player_start
-	stop
 
 
 :ready

game/rooms/room12/room12.tscn

@@ -90,4 +90,3 @@ position = Vector2( 340.052, 298.812 )
 position = Vector2( 542.824, 468.193 )
 script = ExtResource( 5 )
 global_id = "player_start"
-is_start_location = true