Implement equals for Point

Fixes bug in distribution of snippet weights: Multiple equal points could
be in frontier and unvisited, therefore processed twice. Now set of points
adheres to set semantics (compares points by coordinates instead of reference).

bofa/src/main/scala/bot/cortex/SnippetAI.scala

@@ -43,7 +43,9 @@ class SnippetAI extends Tactical {
     def runner(frontier: Set[Point], distance: Int): Unit = {
       if (frontier.isEmpty) return
 
-      // process the current frontier and build the new ones
+      dbg(s"""Frontier[dist= $distance]: ${frontier.mkString(",")}""")
+      
+      // process the current frontier and build the new one
       val nextFrontier =
         frontier filterNot { visited(_).get } flatMap { p =>
           visited(p) put true

bofa/src/main/scala/bot/environment/topology/Point.scala

@@ -8,6 +8,15 @@ class Point (val x: Int, val y: Int){
   def +(direction: Direction): Point = this + direction.delta
 
   override def toString: String = s"Point{.x=$x, .y=$y}"
+  def canEqual(a: Any) = a.isInstanceOf[Point]
+  override def equals(that: Any): Boolean =
+    that match {
+      case that: Point => ( that.canEqual(this) 
+                            && this.x == that.x 
+                            && this.y == that.y )
+      case _            => false
+    }
+  override def hashCode: Int = 41 * (41 + x) + y
 }
 object Point {
   def apply(x: Int, y: Int) = new Point(x, y)