Resolve "Time to refactor utils?"

bilby/core/utils.py

bilby/core/utils/__init__.py

bilby/core/utils/calculus.py

bilby/core/utils/cmd.py

bilby/core/utils/colors.py

bilby/core/utils/constants.py

bilby/core/utils/conversion.py

bilby/core/utils/counter.py

bilby/core/utils/docs.py

bilby/core/utils/introspection.py

bilby/core/utils/io.py

bilby/core/utils/logger.py

bilby/core/utils/plotting.py

bilby/core/utils/progress.py

bilby/core/utils/samples.py

bilby/core/utils/series.py

bilby/gw/detector/interferometer.py

bilby/gw/detector/strain_data.py

bilby/gw/utils.py

bilby/gw/waveform_generator.py