add -c,-s,-V,-i options: -c change the symlink to target to the specified version. -s handle a specific version for command -L|V|e|r. -V displays available version. -i import extra configuration file from a version to another

allow to use a different version of configuration file than the frontend file if any of -c/m/C is providen. Version symlink point now to the directory instead of the file itself which allow to have extra configuration file

pass resolve file to cdb format. mark ss_resolve_pack() deprecated. Add ss_resolve_{read_cdb,write_cdb,add_cdb,add_cdb_uint,find_cdb}()

do not force directory for external and optional dependencies,return 2 in parse_service_before() if the service is already parsed