Add gas bomber skill-shot vessel

tests/_gas_bomb_aim_preview.gd

@@ -0,0 +1,38 @@
+extends Node2D
+
+
+func _ready() -> void:
+	GameState.buildings.clear()
+	GameState.extractors.clear()
+	GameState.transporters.clear()
+	GameState.vessel_levels["unlock_gas_bomber"] = 1
+	var main: Node = load("res://Main.tscn").instantiate()
+	add_child(main)
+	main.get_node("BackgroundLayer").visible = false
+	main.get_node("AsteroidField").visible = false
+	main.get_node("PlanetField").visible = false
+	main.get_node("BuildingField").visible = false
+	main.get_node("EnemySpawner").set_process(false)
+	main.get_node("AsteroidField").set_process(false)
+	var fleet: Node = main.get_node("Fleet")
+	fleet.spawn_ships(3, Vector2.ZERO, PackedStringArray([
+		GameState.VESSEL_INTERCEPTOR, GameState.VESSEL_SHIELD,
+		GameState.VESSEL_GAS_BOMBER]))
+	var skill: GasBombController = main.get_node("GasBombController")
+	skill._process(0.0)
+	main.get_node("Camera2D").zoom = Vector2(1.8, 1.8)
+	var button: Control = main.get_node("UI/GasBombButton")
+	var press := InputEventScreenTouch.new()
+	press.index = 9
+	press.position = button.global_position + button.size * 0.5
+	press.pressed = true
+	skill.handle_touch(press)
+	var drag := InputEventScreenDrag.new()
+	drag.index = 9
+	drag.position = press.position + Vector2(-245, -235)
+	skill.handle_drag(drag)
+	for offset in [Vector2(-65, 0), Vector2(45, -45), Vector2(55, 65)]:
+		var enemy: Node = load("res://Enemy.tscn").instantiate()
+		enemy.position = skill.aim_target + offset
+		enemy.speed = 0.0
+		main.add_child(enemy)