v1.2.0

What's included:

• Adds export_csv method to bio_check.verifier.Verifier() for observables output generated from Verifier().get_verify_output().
• Adds two forms of visualization to Verifier(): visualize_outputs() and visualize_comparison().
• Bug fixes for SBML request handling.
• Polling timer update for internal methods.
• Other updates as needed.