mask eclipse projects of unsupported projects

So they will not be imported by default into an Eclipse workspace.

Change-Id: Iaa03fdded2a964ee6505b9df239bd0ad2ae542d6
Reviewed-on: http://gerrit.esdi-community.eu/3317
Tested-by: Jenkins <sitemple@igd.fraunhofer.de>
Reviewed-by: Simon Templer <simon.templer@igd.fraunhofer.de>