Explore nestle as a possible addition to the best fit process

[Gabriel-p]

Nested Sampling is a computational approach for integrating posterior probability in order to compare models in Bayesian statistics. It is similar to Markov Chain Monte Carlo (MCMC) in that it generates samples that can be used to estimate the posterior probability distribution. Unlike MCMC, the nature of the sampling also allows one to calculate the integral of the distribution. It also happens to be a pretty good method for robustly finding global maxima.

• Repo: https://github.com/kbarbary/nestle
• Docs: http://kylebarbary.com/nestle/

Related: #244, #359

[Gabriel-p]

Merged into #487