anchor.diff:  REFERENCE   1  (bases 1 to %d)
     AUTHORS   .
     TITLE     Direct Submission
  -  JOURNAL   Exported %s %2d, %d from SnapGene Viewer 4.0.5
  +  JOURNAL   Exported %s %2d, %d from GSL SnapGene generator
  +            http://pubs.acs.org/doi/abs/10.1021/acssynbio.5b00194
               http://www.snapgene.com
   FEATURES             Location/Qualifiers
        source          1..%d
                        /organism=\"synthetic DNA construct\"
                        /mol_type=\"other DNA\"
                        /note=\"color: #ffffff\"
  -"           "Exported" // snapgene fails to color anything if it's named anything else locusName 
  +"           locusName 
               totLength  // header line locus length
               now.Day (mon.[now.Month-1]) now.Year  // header line date
               totLength  // length for REFERENCE line
  
positive.code: 
          let path = sprintf "%s.%d.dna" tag 
                      (match a.id with 
                          | None -> failwith "unassigned assembly id in %s" a.name
                          | Some(i) -> i 
                      )
                      |> opj outDir
  
negative.code:         use outF = new StreamWriter(path)
          let w (s:string) = outF.Write(s)
          
          // "Exported" // snapgene fails to color anything if it's named anything else locusName 
          let locusName = sprintf "Exported GSL %s" tag
          let totLength = a.dnaParts |> List.map (fun p -> p.dna.Length) |> Seq.sum
          let now = DateTime.Now
          (* // constraints on header format per SnapGene direct correspandance
  