*TW 27/06/22*
- [Issues [102](https://github.com/TeamLEGWORK/LEGWORK/issues/102)] Make SNR functions notice when you change confusion noise
- `Source.get_snr()` now takes all `sc_params` as arguments for re-interpolation etc
- `Source.get_snr_stationary` and `Source.get_snr_evolving` have the same parameters added as above
- All functions in `snr` now take `**kwargs` that are passed directly to `psd.power_spectral_density` for maximum flexibility