Provide Export view also on simple document

Export views can also be interesting for single documents.

For a standard document view url like http://server/nuxeo/nxpath/somepath@view_document we could have

http://server/nuxeo/nxexport/somepath@rss
=> give RSS feed on document historay (Audit syndication)

http://server/nuxeo/nxexport/somepath@atom
=> give ATOM feed on document historay (Audit syndication)

http://server/nuxeo/nxexport/somepath@xl
=> provide MS Excel export of all document properties

http://server/nuxeo/nxexport/somepath@pdf
=> provide PDF rederning of the document (table for meta-data + digest for all attached files)
(preiew available in seam-pdf addon)