Update 7.1 alpha

[h2]CHANGE LOG[/h2]

Corrected mistakes

• Fixed a texture bug on the poster in front of the entrance to one of the halls in the tunnels.
  
• Fixed a bug where zombies passed through the extreme concrete wall at the entrance to the store.
  
• Fixed a bug where some items fell through the train floor.
  
• Fixed a bug where it was possible to fill plastic with water without contact with water.