zps_deadblock v1.1

changes:

- fixed door in subway (they now open in the right direction and will kill players in case of blocking).
- fixed the door near water room. They are now open all the time and cannot be blocked.
- Added a cab in the car tunel.
- Moved zombie spawn from the car tunel to the backyard.
- Fixed some sounds.
- Added a light in one of the stairwells to make the visibility better for zombies.