FleeMap exception when border coords of baseMap are clear

Hey, I believe I've found some unintended behavior with FleeMap.

Here is a snippet to reproduce:

using GoRogue;
using GoRogue.MapViews;
using GoRogue.Pathing;

...

// Arbitrary map size.
var goalStateMap = new ArrayMap<GoalState>(32, 32);

// Fill the map up with clear state.
for (int x = 0; x < goalStateMap.Width; ++x)
{
    for (int y = 0; y < goalStateMap.Height; ++y)
    {
        goalStateMap[x, y] = GoalState.Clear;
    }
}
// Arbitrary goal position.
goalStateMap[5, 5] = GoalState.Goal;

// Arbitrary distance method.
var goalMap = new GoalMap(goalStateMap, Distance.EUCLIDEAN);
// Arbitrary magnitude value.
var fleeMap = new FleeMap(goalMap, 1.2);

goalMap.Update();

The .Update() call at the end will raise

GoRogue.Pathing.GoalState GoRogue.MapViews.ArrayMap`1[[GoRogue.Pathing.GoalState, GoRogue, Version=2.6.4.0, Culture=neutral, PublicKeyToken=null]].get_Item(GoRogue.Coord ): System.IndexOutOfRangeException: Index was outside the bounds of the array.

To fix this, the outer edges can be set to GoalState.Obstacle:

var goalStateMap = new ArrayMap<GoalState>(32, 32);
for (int x = 0; x < goalStateMap.Width; ++x)
{
    for (int y = 0; y < goalStateMap.Height; ++y)
    {
        if (x == 0 || x == goalStateMap.Width - 1 || y == 0 || y == goalStateMap.Height - 1)
        {
            goalStateMap[x, y] = GoalState.Obstacle;
        }
        else
        {
            goalStateMap[x, y] = GoalState.Clear;
        }
    }
}
goalStateMap[5, 5] = GoalState.Goal;

var goalMap = new GoalMap(goalStateMap, Distance.EUCLIDEAN);
var fleeMap = new FleeMap(goalMap, 1.2);

goalMap.Update();

The above snippet no longer raises the exception.

I think the issue would be fixed if one or both of these lines also checked if the Coord was in bounds of the map (similar to how GoalMap checks if the Coord is contained in the walkable set): https://github.com/Chris3606/GoRogue/blob/master/GoRogue/Pathing/FleeMap.cs#L160 https://github.com/Chris3606/GoRogue/blob/master/GoRogue/Pathing/FleeMap.cs#L170 But I haven't had time yet to test it.

Or perhaps is this intentional behavior for performance reasons?

Chris3606 / GoRogue

FleeMap exception when border coords of baseMap are clear #211