code: def scanABFfolder(abfFolder):
      
      assert os.path.isdir(abfFolder)
      filesABF=forwardSlash(sorted(glob.glob(abfFolder+"/*.*")))
      filesSWH=[]
      if os.path.exists(abfFolder+"/swhlab4/"):
          filesSWH=forwardSlash(sorted(glob.glob(abfFolder+"/swhlab4/*.*")))
      groups=getABFgroups(filesABF)
      return filesABF,filesSWH,groups
docs: scan an ABF directory and subdirectory. Try to do this just once.
      Returns ABF files, SWHLab files, and groups.