Output level normalization

[artfwo]

Output level for Perlin noise / fBm is wildly different depending on synth settings. Ideally it should be constant so we always get the same volume for any X or Y.

Possible solutions to explore:

• When regenerating seed, pre-calculate global optimums for every octave for all 4 gradient arrays using either brute force or optimization method like simulated annealing.
• Now that Andes uses simplex noise with a better analytical derivative, peaks can be calculated precisely by solving N'(x)=0 equation and substituting the solution in the noise function.