def add_files filearray, config={}
      filearray.each do |e| add_content(e, config.dup); end
    end
def add_files filearray, config={}
      filearray.each do |e| add_content(e, config.dup); end
    end
supply an array of files to the multibuffer. These will be read
  as the user presses next or last etc.