Added tracking of Kandler and Steele's remaining trait statistic.  This is done by calculating the interval from generations (specified) to timesteps, and then starting a snapshot at maxtime - interval-in-timesteps, and stopping at maxtime.  The number of surviving traits per locus is calculated and stored along with the maxtime snapshot.

I am concerned at some rules (e.g., conformism) privilege trait 0 or 1, but in neutral copying I do see this trait drift out.  Need to devise some careful tests for conformism and anticonformism.  But very close on this.

Might want to do multiple Kandler intervals per simulation, though?