Fixed dialyzer errors

```
  make dialyzer
    Checking whether the PLT is up-to-date... yes
    Proceeding with analysis... done in 0m1.27s
  done (passed successfully)
```

And also fixed some styling issues
Line 156 is too long: "    [spawn(mas_conc_agent, start, [Agent, Arenas, SP, Cf]) || Agent <- lists:nthtail(length(Froms), Agents)];".