Random school placement
Schools can now be randomly assigned a spot in the grid ('random') or a random spot per neighbourhood ('random_per_neighbourhood'). This last one also works when n_schools > n_neighbourhoods and vice versa.
If n_schools >= n_neighbourhoods, every neighbourhood gets an equal amount of schools initially (schools are randomly assigned a spot in their neighbourhood). The remainder is randomly assigned a neighbourhood and then randomly assigned a location in that neighbourhood.
If n_schools < n_neighbourhoods, schools are assigned a random neighbourhood (without replacement of neighbourhoods) and then a random location within that neighbourhood.