Test/new tests

[FrancescaDelGaudio]

Tests added on all systems (Messi, Bruteforce, LbBruteforce:

• Concurrency: tried some configurations of #threads,#k, in order to raise concurrent accesses and prevent race conditions.
• Memory leaks: tried to run in a row different instances of the systems to figure out if memory was allocated and deallocated correctly.
  All tests passed.
  -Useless commented code on BF and LbBF deleted to make code nicer.