Legwork

*TW, 5/11/21*
Small changes to visualisation code and updates to tutorials/demos with the new code
- allow user to specify weights in `Source` and visualisation functions
- allow user to customise sensitivity curve in any use of `plot_sources_on_sc`
- `legwork.__version__` now prints the version number
- Add new demo about verification binaries and other miscellaneous docs fixes

*TW, KB 31/10/21*
Major version change as we've added a significant enhancement with the new non-average SNR calculations.

- Change `snr` module to allow the calculation of non-averaged SNR using exact inclination, sky position and polarisations
- Let users specific inclination, sky position and polarisation in `Source` instantiation
- Add `VerificationBinaries` class to `Source` module for convenient access to LISA verification binary data from Kupfer+18
- Change max line length in code from 80 to 110 to increase readability

*TW, 26/10/21*
- Avoid plotting merged sources in any of the automatic routines
- Allow source class evolution code to handle sources close to their merger
- Ensure SNR calculation works if some sources have merged and produces no warnings
- Change default behaviour of Source class with interpolate_g - no longer always interpolate, only when the collection of sources is fairly large or it contains eccentric sources
- Add a warning for if all timesteps are too close to the merger (based on `t_before`) and hence evolution can't happen

*TW, 25/09/21*
- Avoid LSODA warnings by preventing integration from getting near the singularity at the merger
- Allow user to select how long before a merger to stop integration

*TW, 19/05/21*
- Change visualisation module to be more flexible with **kwargs (allow any for dist plot and add linewidth to sensitivity curve function)
- Change Source.get_snr() to allow re-interpolation of the sensitivity curve for convenience (and fix the warning so it works properly)

*TW, 12/04/21*
- Allow the computation of merger times with ``get_merger_times``
- After computing, times are used automatically
in subsequent SNR calculations to avoid doubling up the computation
- Add ``evolve_sources`` function that evolves sources through time, updates merger times and if necessary marks them as merged
- Merged sources are ignored in other computations (e.g. strain and SNR)
- Add ``ret_snr2_by_harmonic`` to eccentric snr functions to allow the user to get the SNR at each harmonic separately instead of the total
- Add minor fixes to snr for evolving sources for when sources are closes to merging