Plague 3.17 - changes galore!

• survivors now can have squad behavior and formations (extensions to come)
  
• Sean Lange has added walking animation for Survivors
  
• survivors now avoid heat (they run away from fire)
  
• guns now start with a full clip of ammo
  
• capped the number of zombies and hives to stop massive slow downs
  
• scaled the number of permissible zombies to the number of remaining hives
  
• removed a bug where survivors try to pick up a weapon they already have
  
• fixed a bug where the laser charged while the simulation was paused
  
• made the player exempt from sharing weapons with other survivors
  
• added a drop weapon key (x), drops your current weapon and switches to another weapon if you have one (I know there is an intermittent bug with this, bug reports welcome)
  
• have not added all of Sean Lange's additional art (I'm out of weekend).