correction of infection

Increased chance of NPC infection
Changed the names of NPCs
Added the virus_player console command that enables and disables player infection.

Broken new version

Increased chance of NPC infection
Changed the names of NPCs
Added the virus_player console command that enables and disables player infection.

Code rewritten
Increased chance of NPC infection
Slightly improved chance to kill a Walking with a shotgun

fix

Initial addon creation.