astarnode.kod:
Updated CalculateMovementCost(), Constructor(), and TryNewParent()
They now taka a diagonal parameter and add costs differently as such.
10 = Cardinal Movement
14 = Diagonal Movemtn
Updated CaclculateHeuresticCost() to use 10 for each square for
compatibility with diagonal Movement Cost

astarpath.kod:
added poNextMove for use in single-step movement
fixed plDebugItems handling and cleanup
added CalculateStep() for single-step movement
added diagonal calculations to ScanNode()

monster.kod:
added poAStarPath to hold our path object per-monster
modified MoveTowards(), checks if Astar enabled, if so, creates/uses an
astar path from current location with Astar.CalculateStep()