Implement more methods for Bayesian model updating

[jgrashorn]

Implementing more methods (Variational, Hamiltonian MC, MCMC...) adds more choices! The ones below are some suggestions from the top of my head, the list can be shrunk or expanded on.

Basic

• [x] (Multi-modal) Maximum Likelihood
• [x] (Multi-modal) Maximum a posteriori

MCMC

• [x] MH
• [x] TMCMC
• [ ] X-TMCMC [paper]
• [ ] (X-)BUS [paper]
• [ ] DRAM [paper]

Hamiltonian MC

• [ ] basic HMC
• [ ] NUTS [paper]

Variational

• [x] Laplace approximation
• [ ] Multivariate Gaussian [paper]
• [ ] Transport Maps [shameless self-citation] [website]
• [ ] Normalizing Flows [paper]
• [ ] (C)VBMC [paper] [code]