Adding the Curtsdotter 2011 extinction framework

[TanyaS08]

Curtsdotter et al. (2011) looks at deletions in both static and dynamic networks. Need to make the extinction framework flexible enough to account for the dynamic component

DOI: 10.1016/j.baae.2011.09.008

[TanyaS08]

I've looked at this - I think it will come down to being a case of doing a 'point extinction' ( #1 ) for every 5000 time stamps (as well as rerun _spp_removal()