Modify missing outputs

[adespawn]

Stricter no outs verification
Fix script crashing on lack of any outputs

[adespawn]

Stack trace for mentioned crash:

Traceback (most recent call last):
  File "[...]/sinol_make/__init__.py", line 83, in main
    main_exn()
  File "[...]/sinol_make/__init__.py", line 73, in main_exn
    command.run(args)
  File "[...]/sinol_make/commands/run/__init__.py", line 1226, in run
    self.set_scores()
  File "[...]/sinol_make/commands/run/__init__.py", line 1099, in set_scores
    self.possible_score = self.contest.get_possible_score(self.groups, self.scores)
  File "[...]/sinol_make/contest_types/default.py", line 67, in get_possible_score
    if groups[0] == 0 and len(groups) == 1:
IndexError: list index out of range