- Changes the warning to an Error
- Adds method to InterferometerStrainData to check if a time is within
  the span
- Clean up logging of warning if the geocent_time is within the data
  span
- Print infomation about the injection to the terminal

Closes #115

Adds the option to add a label to the saved data and plots associated
with Interferometer

- Move logic from `fill_prior` to its own method
- Call in `sample` to ensure the full set is sampled

Ensure that if the log level is set from the setup_logger call, all
handlers also get updated.

Closes #110

Implemented append, extend, insert methods from super class with a check that makes sure that the interferometers stay consistent.

Adds `set_strain_data_from...` functions to allow easy setting of the
data.

The tupak.core.prior call in the core/__init__.py file was accidently
removed during testing. This puts it back in.

If the prior is not given to the likelihood when using the marginalized
likelihood, marginalization cannot be safely performed. This adds a
check and raises a ValueError if it is not set.

Closes #88