Added a basic pathfinding test
Added A* pathfinding for robots when the path is known.

This reworked a bit of logic so that each robot has an independent map, which will, despite not being implemented at the moment, start out blank
Todo: draw the robots/paths, the easiest place to hook this in would probably be in the move[Up|Down|Left|Right] methods, either by making the robot drop breadcrumbs there, or making simply painting a circle where the robot is.
Fixed the key panel, now takes arbitrary markers and stretches.

Since I broke it in the last commit by adding 'S' to the marker list, since the robots need to come home.
I am not sure if the colors were ever in the right order.