Added debug option to Spaceship to insta-self destruct.
Spaceships now respawn at last checkpoint location on death.
Added respawn points to every checkpoint.
Menu should now work during gameplay for PS3/PS4/Xbox360 controllers.
Debug self-destruct now slowly damages rathen than insta-killing player.
Added spaceships gettting damage from lasers.
Generated cubey towers can be destroyed by lasers.
Lasers now spawn explosions where they hit.