Restore checkpointing to a working version.
Restore checkpointing to a working version.

adamallo/beast-mcmc,beast-dev/beast-mcmc,4ment/beast-mcmc,maxbiostat/beast-mcmc,beast-dev/beast-mcmc,maxbiostat/beast-mcmc,adamallo/beast-mcmc,4ment/beast-mcmc,beast-dev/beast-mcmc,adamallo/beast-mcmc,4ment/beast-mcmc,4ment/beast-mcmc,adamallo/beast-mcmc,beast-dev/beast-mcmc,maxbiostat/beast-mcmc,beast-dev/beast-mcmc,maxbiostat/beast-mcmc,4ment/beast-mcmc,maxbiostat/beast-mcmc,adamallo/beast-mcmc,4ment/beast-mcmc,beast-dev/beast-mcmc,maxbiostat/beast-mcmc,adamallo/beast-mcmc