- Adds debug information
- If no data is in a given segment, a nan will be produced. Rather than
  summing this, the code will now replace it with zero and spit out a
  debug message to the effect.

As far as I can tell this should not be here (transient=True) in this
case. Nevertheless, I'm leaving it commented as this is quite a core
routine and I wish to remind myself to investigate it further.

- Adds a simple interface to get grid search given uniform prior
- Fixes detector -> detectors bug (previous versions, the constrains
  where not actually set)
- Adds title functionality to plot2D

- Addresses incorrecelt named attributes and prevents error if
  sftfilepath is not specified

Also adds thetas_at_ref data to the Writer object

Now forces use of dtglitch = None for no glitches

1) Adds 'add_noise' option (defaults to true)
2) Better checking of Writer for if all glitch parameters have the same
length (avoid strange errors)
3) Fixes issue in which the tqdm ignore command was itself ignored

Transforms the single pyfstat.py into a python module splitting the
relevant code into separate sub-files in pyfstat. This should result in
improved readability.