Toy example for testing dimensionality of GPO

We want a good idea of how many initial points are required for exploring `n-D` space, i.e. for the latin hypercube should we go for `k*n`, `k*2^n`, `K*n^2`, etc.

We should use one of the standard multidimensional surfaces (egg box or Rosenbrock) and test the optimisation of the minima for a variety of `n` and initial points.