[cmdline][verification] Revise the semantics of the option for selecting goals.

Here the revised semantics:
- Option -T <theory_name> select only the goals of theory <theory_name>
- Option -g [<theory_name>:]<goal_name>,...,<goal_name> select only the list of
  <goal_name> from the <theory_name>, or from all theories.
- If no -T and -g are provided, all goals (from all theories) are selected.