--This model has a slider for initial # of red (infected) agents.
--The slider for Transmission Rate allows the user to control how fast the infection spreads using code the has a % chance of passing on the disease.
--the turtles are using a new trait called 'ticks-ill' that counts how long the turtle is infected, after a certain amount of time, it will die (be deleted)
--The recovery slider allows you adjust the percent chance that a sick turtle becomes healthly.