The `generate_component_masses` function generates component masses
from any pair of masses with sufficient information to do so,
`generate_mass_parameters` now takes any pair of mass parameters with
sufficient information and adds all of the mass parameters.

bilby/gw/likelihood/multiband.py and test/gw/likelihood_test.py: fix calibration errors in multiband likelihood and add tests of multiband likelihood for non-zero calibration errors