for project export, work on a copy of the project object

Change-Id: I28a85223feb4ef1b972f42638dd8cdc570f81ff4
Reviewed-on: http://gerrit.esdi-community.eu/3202
Tested-by: Jenkins <sitemple@igd.fraunhofer.de>
Reviewed-by: Simon Templer <simon.templer@igd.fraunhofer.de>