def initialize(options={})
      @styles = Styles.new
      @worksheets = SimpleTypedList.new Worksheet
      @drawings = SimpleTypedList.new Drawing
      @charts = SimpleTypedList.new Chart
      @images = SimpleTypedList.new Pic
      # Are these even used????? Check package serialization parts
      @tables = SimpleTypedList.new Table
      @pivot_tables = SimpleTypedList.new PivotTable
      @comments = SimpleTypedList.new Comments


      @use_autowidth = true

      self.date1904= !options[:date1904].nil? && options[:date1904]
      yield self if block_given?
    end
lets come back to this later when we are ready for parsing.
def self.parse entry
io = entry.get_input_stream
w = self.new
w.parser_xml = Nokogiri::XML(io.read)
w.parse_string :date1904, "//xmlns:workbookPr/@date1904"
w
end
Creates a new Workbook
The recomended way to work with workbooks is via Package#workbook
@option options [Boolean] date1904. If this is not specified, date1904 is set to false. Office 2011 for Mac defaults to false.