Fixing circular imports and CircleCI tests

[alexpiet]

• [x] Pins markupsafe version to 2.0.1 in test environment, and thereby resolves #810.
  • See PR #811 for details
• [x] Removes data_access.utilties dependence on data_access.loading and thereby resolves #808

There were three functions in utilities that used loading.

• [x] utilities.check_for_model_outputs()
  • This is a duplicate!?!? of loading.check_if_model_output_available so I am removing this function
• [x] utilities.model_outputs_available_for_behavior_session()
  • This is a duplicate!?!? of loading.check_if_model_output_available so I am removing this function
  • Called by reformat.add_model_outputs_availability_to_table()
    • [x] so I removed reformat.add_model_outputs_availability_to_table()
    • in turn called by reformat_experiments_table(). So I removed that function call.
• [x] utilities.get_behavior_session_ids_to_analyze()
  • On slack @matchings says its ok to remove this function, so I am removing it.