Added concurrent queue
CallBack added

added callback function which checks if something is a solution and ends
execution if it is.
let moves keep parents, not gridtoestanden
create byte array before passing to gridtoestand
Solver fully static again, split Zoek
moved common part of Zoek to SituatieGevonden
Made folders, added prioqueue
Heuristic search. Superfast, but can make mistakes

Still needs some debugging, but it's doing 0.02 seconds on the hardest
problem
Commentaar
slow on 4
correct heuristic
okay, now it's correct

forgot to make the change when moving backwards
Merge branch 'weirdprio' into prioqueue