let make_group g ?(name = "") =
if ((not(List.mem g !num_groups)) && (g>0))
then begin
num_groups := List.sort (compare) (g::!num_groups);
let tgroup = { num = g;
name = ref name;
size = ref 0;
proj = make_project 0; (* Create really different empty projects *)
} in
all_groups := tgroup::!all_groups;
end