add fields: Groups, depends, requiredby. Pass through new graph function to compute the dependencies. Use new function tree_iscurrent, tree_isenabled

rename service_resolve_svtree function to service_intree. Rename struct ss_resolve_graph_style to info_graph_style

deprecated -c option and use -z instead. This change is made to be consistent with option between tools

Prevent symbol lookup error in commands linked to lib66.so:

66-tree: symbol lookup error: /usr/x86_64-pc-linux-gnu/lib/lib66.so.0.2:
undefined symbol: MAXDEPTH