void Update()
 {
     if (Input.GetKeyDown(KeyCode.Alpha1))
     {
         towerToBuild = TowerToBuild.Sniper;
         // Debug.Log("Now building sniper towers.");
     }
     if (Input.GetKeyDown(KeyCode.Alpha2))
     {
         towerToBuild = TowerToBuild.Canon;
         // Debug.Log("Now building canon towers.");
     }
 }
 public void SetTowerToBuild(int nextTower)
 {
     towerToBuild = (TowerToBuild)nextTower;
 }