Reads output of ADMB MCMC report containing estimated distributions. The .hst report contains information about the MCMC analysis: the sample sizes (specied with the -mcmc command-line option), the step size scaling factor, the step sizes, and information about the posterior probability distribution (e.g., the mean, standard deviation, and lower and upper bounds). For each simulated parameter, a range of values (with step sizes reported in the "step sizes" section of the .hst file) and their simulated posterior probabilities is reported. Plotting the first column (parameter values) on the x-axis and the second column (simulated probabilities) on the y-axis can be a convenient way to make a visualization of the posterior probability distribution.