Initial values

[oliviergimenez]

Would be great to come up with a function to generate initial values, including for latent states. And/or reiterate the advice that if you don't need the latent states, then a marginalized likelihood is fine (nimbleEcology) and you don't have the latent states anymore, so no initial values to pick for these. See https://r-nimble.org/html_manual/cha-mcmc.html#sec:initMCMC