Allow users to specify multiple baselines

[TeaganKing]

We will want to consider how we loop through these baselines and also duplicate sections of the configuration file.

base_case_name should be a list, and base_case_output_dir would also need to be a list.

Additionally, the timeseries case names should be pulled from the global parameters.

[TeaganKing]

@gunterl was also interested in a capability of multiple baselines for SMB plots