create "pareto front" mode

[happyjack27]

create a "pareto front" mode that, instead of searching for global optima, searches for non-dominated solutions.

https://en.wikipedia.org/wiki/Multi-objective_optimization

that means all the weight sliders would be irrelevant - should just disable them in the mode to make that clear.

[happyjack27]

http://citeseerx.ist.psu.edu/viewdoc/download;jsessionid=DB2C0FB4F2159957393DAD16E5B755B6?doi=10.1.1.542.385&rep=rep1&type=pdf

[happyjack27]

http://www.isical.ac.in/~sriparna_r/amosa_final_indraft_twoc.pdf