Incorrect coordinates of the all_losses matrix

[doducchien]

In plots/chapter0.py
At line 106: ax1.scatter(b_minimum, w_minimum, all_losses[bidx, widx], c='k')
We must pass all_losses[widx, bidx] instead of all_losses[bidx, widx].
Because we use meshgrid of (b_range, w_range)