Update Point.java to properly override equals

src/edu/caltech/cs2/lab08/Point.java

      * Returns true if the point passed has the same x and y coordinate as
      * this point, or false otherwise.
      */
-    public boolean isEqual(Point point) {
-        if (point == null) return false;
-        int x = point.x;
-        int y = point.y;
-        return (this.x == x && this.y == y);
+    @Override
+    public boolean equals(Object o) {
+        if (!(o instanceof Point)) { 
+            return false; 
+        }
+        Point p = (Point) o;
+        return (this.x == p.x && this.y == p.y);
     }
 }