Added some information about running the MCMC on the README.
Created vignette about running MCMC simulation.
Minor changes to functions like setting default values and changing a few mistakes in the MCMC_allplots code.  Created new function analyze_MCMC that calculate the posterior means for alleles, z values, and rho values after running contam_MCMC.
Merge branch 'master' of https://github.com/eriqande/SNPcontam