Merge branch 'update_prior_files' into 'master'

CHANGELOG.md

examples/injection_examples/basic_tutorial.py

examples/injection_examples/change_sampled_parameters.py

...tion_examples/create_your_own_time_domain_source_model.py

examples/injection_examples/eccentric_inspiral.py

examples/injection_examples/how_to_specify_the_prior.py

examples/injection_examples/sine_gaussian_example.py

examples/supernova_example/supernova_example.py

test/prior_files/binary_black_holes.prior

test/prior_test.py

tupak/gw/prior.py

tupak/gw/prior_files/GW150914.prior

tupak/gw/prior_files/binary_black_holes.prior

tupak/gw/prior_files/binary_neutron_stars.prior