Model for epochs with variable migration and coalescence rates back in time.
Merge branch 'feature/psmc_simulations' of https://github.com/mailund/IMCoalHMM into feature/variable_migration_model
Initial script
Changed option parser to argparse

The opt parser package is deprecated
Reading alignments for all three configurations.
Merge branch 'feature/variable_migration_model' into develop
Bumped versions
Merge branch 'release/different_options' into develop
Merge branch 'develop' into feature/psmc_simulations