Compute a binned version of a map or set of maps.
 
  INPUT
 
      volume:           single 3d or 2d map to bin
                          or
                        cell array of 3d ( or 2d) maps
 
 
      order:            integer number:
                        0: volume remains unchanged
                        - default: 1
 
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   OUTPUT
 
      binned_volume:    binned volume (or cellarray of volumes)
 
 
   EXAMPLE
   
   volume=dynamo_bin(volume,1);
   volumes=dynamo_bin({volume1,volume2},1);
   
   NOTE:
 
      This function requires data with even dimensions.
      If the provided data has odd dimensions, the dimensions of the 
      binned volume will be rounded down.