refactor patrolbot

replace complicated let/dotimes/append/setf code with a simple repeat/collecting loop
misc minor changes
initial commit of pathfinder
Add permutate function
Copy basic structure from patrolbot

They seem to have similarities... In case there's another one with these functions I'll think about a build/packaging solution
Mark actual execution start
Add pop-instruction
Build basic final structure
Add single loop find dirt impl
only use one main incrementing loop var
finish find-dirt-locations
work on build-instructions
add todo for tomorrow