0.1 -> 0.2 
    Added function for power for F2 intercross
0.2 -> 0.3
    Corrected function for discount factor for F2 intercross.
0.3 -> 0.31
    Corrected F2 power function and detectable effects function.
    It was not doing the right thing for non-zero marker intervals.
    Analytical error.
0.31 -> 0.32
     Changed the dominance coding to be consistent with Karl's R/qtl.
