rewrote the equatin N(t+1); before it used rcrt(), which, I think, was double counting N by using N as an initial conidtion in the calucation of Bfin, and then multiplying by it again after
Added rootfun to stop integration.  Probably don't need it
#added variable iyr, so can be plotted excluded initial transient years
increased length of sim to check for coexistence