def merge!(rh)
      rh.each_pair do |k, v|
        # v is a TimeCollector
        if self.has_key?(k)
          self[k].merge!(v)
        else
          self[k] = v
        end
      end
    end
def merge!(rh)
      rh.each_pair do |k, v|
        # v is a TimeCollector
        if self.has_key?(k)
          self[k].merge!(v)
        else
          self[k] = v
        end
      end
    end
merges multiple ResultsHash's