tunasim (modification from catsim)

- Some code was changed for the recent Mltifan CL test
- Some code was added for SS3 test (.dat and .ctl)
- Recruitment calculation code was added using Beverton-Holt
stock-recruitment relationship
- SS3-like logistic maturity schedule (age dependent) was added
- SS3-like selectivity options (Logistic, Double Logistic, and Double
normal) was added