Updating metrics of diversity to take into account graph structure. This will have to change in the future.

we changed the way we store agents in Simulation. Now it is a vector of vector of agents, and it seems to perform much better. Thus we are merging all this in v1.0

added hamming distance for x history metrics, and changed structure of agents so that t_hist is now a Float64 (otherwise, conflicts happen because dt can be less that Float16 error)

Test have also been modified, because it seems that this change also changes the random seed.