make exclusive -s and -c options.
use new environment function from oblibs.
less HEAP memory usage.

simplify interface of service_is_g and its functionality, provide service_get_treename as replacement

rename service_resolve_svtree function to service_intree. Rename struct ss_resolve_graph_style to info_graph_style

deprecates options -c|m|C|i at 66-enable and add option -I. Pass to the new configuration file format at ssexec_env.

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