random permutation (using gsl) of neighbour fields
validity check for agent;
mutation counter determines immunogenicity;
infection radii are now part of the world;
new method for generating world using agent for optimizing parameters
corrected subtle bug (if no infection, disease has been ended immediately!)
corrected breaking;
added error printing if wrong state hosts appear in lists;
when processing lists, next must ALWAYS be set before processing/changing the list elements!!