def get_column_width(column_index = 0)
      width = get_column_width_raw(column_index)
      return RubyXL::ColumnRange::DEFAULT_WIDTH if width.nil?
      (width - (5.0 / RubyXL::Font::MAX_DIGIT_WIDTH)).round
    end
def get_column_width(column_index = 0)
      width = get_column_width_raw(column_index)
      return RubyXL::ColumnRange::DEFAULT_WIDTH if width.nil?
      (width - (5.0 / RubyXL::Font::MAX_DIGIT_WIDTH)).round
    end
Get column width measured in number of digits, as per
 http://msdn.microsoft.com/en-us/library/documentformat.openxml.spreadsheet.column%28v=office.14%29.aspx