removeEntity(entity) {
    let index = this.entities.indexOf(entity);
    if (~index) {
      this.entities.splice(index, 1);

      index = entity.queries.indexOf(this);
      entity.queries.splice(index, 1);

      this.eventDispatcher.dispatchEvent(
        Query.prototype.ENTITY_REMOVED,
        entity
      );
    }
  }
Remove entity from this query
@param {Entity} entity