Add node metadadata to downloaded zip file

[GoogleCodeExporter]

Business purpose of the feature:
Add all additional information a node carries (metadata) to the downloaded zip 
file.


Requirements:
Check how we should do that. I see are two possibilities:
- Adding additional properties to the downloaded files, if possible. Have to 
check that first
- Add an addtional export xml for each file to the zip. That's the easy way. 
But requires to define an XML format for that.

Technical details:
To be defined.

Original issue reported on code.google.com by thomasha...@googlemail.com on 19 Aug 2011 at 7:40