title: Graphite max of a series with wildcards
body: <p>I'm looking for something similar to sumSeriesWithWildcards, but for max/min. I mean, instead calculating the sum aggregated on the desired fields, it should calculate min or max. I was surprised not to find a maxSeriesWithWildcards call in Graphite library.
  In case it doesn't exist, how could I simulate that ?</p>
  
  <p>Thanks,
  Greetings,
     Sorin</p>