switch to hash map to build the tree graph

src/include/66/66.h

src/include/66/graph.h

src/include/66/tree.h

src/lib66/exec/ssexec_tree_admin.c

src/lib66/exec/ssexec_tree_resolve.c

src/lib66/exec/ssexec_tree_signal.c

src/lib66/exec/ssexec_tree_status.c

src/lib66/graph/graph_build_tree.c

src/lib66/tree/deps-lib/deps

src/lib66/tree/tree_hash.c