scram projects -too-conf improvements

- add BUILDREQUIRE-TOOLFILE and NOCOMPILER flags
- first copy all the tool files from any -tool-conf project e.g. for a patch release get toolfiles from base release tool-conf
- skipped tool files of a base release now automatically skipped in patch release. this should fix the issue if we skip a tool in base release tool-conf and forget to fix patch release tool-conf