Added prior on EBV[0]
Changed to Delta_EBV
Guess maximum EBV from stacked probability densities.
Changed los parameterization to logEBV. Tweaked los MCMC parameters.
Implemented initial exploration to generate l.o.s. guess. Random
states are then generated by perturbing this guess.
Tweaking l.o.s. priors to achieve better convergence.
Changes to default commandline parameters. Decreased number of
steps per star; increased number of steps in l.o.s. fit.