Draft: Replace bayestar_realize_coincs.py

Replace bayestar_realize_coincs.py script to include effects of earth rotation. We have made adaptations to lines 127 - 159. The main change is that we have included a time shift in the antenna function, so that Fplus and Fcross are now arrays corresponding to time samples given by 'tlist' (line 149).

One thing we are particularly unsure of is how to feed this into the snr series - currently we do this by manipulating the time samples to match those of snr_series (line 150).