make plot marginals work

See merge request !294

Added tutorial for fitting a line with x and y

See merge request !284

pymc3.py: explicitly set step method arguments

See merge request !293

 - PyMC3 only applies the step_kwargs and nuts_kwargs arguments
   to the step methods if they are automaticallu allocated. Otherwise,
   it assumes you have already initialised the method with the
   required keywork arguments. This was not being done in bilby, so
   this patch fixes it and does explicitly initialise the step methods
   with values passed to step_kwargs or nuts_kwargs as required.

Attempt to allow compound step methods for PyMC3

See merge request !289

allow beta distribution to have user specified loc/scale

See merge request !291

Remove outdated references in docs to BBH priors

See merge request !288

 - refs lscsoft/bilby#256

Add a check that the outdir exists to plot_trace

See merge request !287

Solves a bug where run will crash if plot=True using dynesty and the
outdir had not previously been made.

Updating tutorial notebooks

See merge request !282

Resolve "Add injection matched filter and optimal snrs to output h5 file"

Closes #217

See merge request !283

# Conflicts:
#   bilby/gw/detector.py

Restructre time frequency tests and fixing some recently surfaced bugs when using time domain models

See merge request lscsoft/bilby!279

Adds two new methods to the result object: kde and posterior_probability

See merge request !278

Resolve "Make Interferometers serialisable and add a to_hdf5 method"

Closes #242

See merge request !273

Resolve "PEP8 Imports"

Closes #207

See merge request !230

- Adds meta_data attributes to the likelihood, interferomer_list and
  interferometers
- Adds mechanism to add likelihood meta_data to the stored meta_data

Resolve #222 Inconsistent use of `priors` and `prior`

Closes #222

See merge request lscsoft/bilby!274

Adds version information to the result object

See merge request lscsoft/bilby!275