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.

1) Update README installation instructions
2) Put all set_up code into seperate named functions
3) Remove underhanded mpl backend setter

Prior to this, the analytic fits data was all for twoF = 60, this
updates this and adds a tag to the filename to make it it clear

Use N=1000 for the recoveries and N=10000 for the test in noise

Issues:
1) If tstart and duration where not explicity searched over, a loop
condition would quickly send the duration to infinity
2) Fixed half norm definition

1) Changes the way the prior is built to be wider than the initial box
2) Fixes error where the F0 and F1 where always chosen in the middle of
the box

Rather than starting with the fully-coherent Vsize, this now starts with
the input Nseg0 (i.e. from the SC search). and works back to Nseg=1.
The user is then left to check the V0 value and whether the search is
appropriate or not. Applies the idea to the follow-up example.