added info on time argument to MCMC roxygen documentation
added info on time argument to MCMC roxygen documentation

NLMichaud/nimble,nxdao2000/nimble,nimble-dev/nimble,NLMichaud/nimble,nimble-dev/nimble,nxdao2000/nimble,nimble-dev/nimble,NLMichaud/nimble,NLMichaud/nimble,nimble-dev/nimble,nimble-dev/nimble,nxdao2000/nimble,nxdao2000/nimble