L4D Tank nextbot fixed

 L4D2 tank nextbot fixed.

This skin arleady exist on steam, but Did not have a model. i  have worked many.

added 4 tank model from steamworkshop.

i just reuploaded its on workshop, but fixed the problem.

NOTICE: Nextbots are NPCs, but they require maps with a "Nav Mesh" to work. 

If your map dont have a "Nav Mesh", you can create it:

• Open the console 
• type sv_cheats 1 
• type nav_generate 
• Garrys Mod reload the map and then you can save the Nav Mesh with nav_save 
• type sv_cheats 0