TransformationWorkspace: allow transformation with custom environment

Change-Id: Ibf3feb32a7706c9e3b1bdbd82909e79cc870287c
Reviewed-on: http://gerrit.esdi-community.eu/3242
Tested-by: Jenkins <sitemple@igd.fraunhofer.de>
Reviewed-by: Simon Templer <simon.templer@igd.fraunhofer.de>