Move point area options to GOToolNode.

[pixelzoom]

For #374

PositionMarkerNode currently has these SelfOptions:

  // pointer areas
  touchAreaDilationX?: number;
  touchAreaDilationY?: number;
  mouseAreaDilationX?: number;
  mouseAreaDilationY?: number;

Consider moving them to GOToolNode, default to zero for GORulerNode.

[pixelzoom]

This was not doable. The superclass (GOToolNode) has no children, the subclasses are responsible for the "look" of the tool. And since pointer areas rely on localBounds, they must be handled by the subclass, after adding child Nodes.