This is preparatory to providing support for workbook properties (and extended properties) in the Excel5 Writer, because properties are stored in the SummaryInformation and DocumentSummaryInformation streams, and not in the workbook stream.
Previously, PHP_OLE could only save a single stream, so this had to be the workbook stream; so document property information was discarded by the Excel5 Writer.
git-svn-id: https://phpexcel.svn.codeplex.com/svn/trunk@77804 2327b42d-5241-43d6-9e2a-de5ac946f064
