added notes on versioning to build config

Change-Id: I4f0c8ece11d98eb7463a79b8a57e44f4d7d0e000
Reviewed-on: http://gerrit.esdi-community.eu/3175
Tested-by: Jenkins <sitemple@igd.fraunhofer.de>
Reviewed-by: Simon Templer <simon.templer@igd.fraunhofer.de>