Choose a random point inside the bounding rectangle of an entity.
@private
@param {object} game Required for game.entities.get().
@param {integer} entity The id of entity to pick a point within.
@returns {object} an point object <code>{"x": 50, "y": 50}</code>.
function choosePointInEntity(game, entity) {
  var position = game.entities.getComponent(entity, "position");
  var size = game.entities.getComponent(entity, "size");
  if (size === undefined) {
    return {
      "x": position.x,
      "y": position.y
    };
  }
  return {
    "x": random.inRange(position.x, (position.x + size.width)),
    "y": random.inRange(position.y, (position.y + size.height))
  };
}