Birth changes:
1. We now use the pair human probabilities.
2. Now we resolve Human-Human conflicts as well
3. We now control births considering ages of humans 20-45 years
4. There's a loop that goes through a 'mini-grid' build around the
tested human in order to find some free space for the new born, if
theres no space for the baby (includes out of bounds), the baby dies!

5. We need to keep improving the code, this change may affect the
parallelized program because I don't consider locks and new possible
shared variables (yet).