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.
0.32 -> 0.80
     Major changes; too many to document.  Changed syntax of many
     commands.  Deleted the simulation commands.  Made the whole
     package more practical.
0.80 -> 0.81
     More complete documentation.  Corrected bug in powercalc
     wrapper function.
0.81 -> 0.85
     - Changed alpha to sel.frac in all arguments to minimize confusion
       between alpha, the level of a test, and the selection fraction.
     - Changed the name of the function "optalpha" to "optselection".
     - The functions "powercalc", "samplesize", and "detectable"
       now accept the arguments bio.var, gen.var, and bio.reps directly; 
       it is not necessary to call "error.var" any more.
     - The functions "powercalc", "samplesize", and "detectable"
       now output the percent variance explained also.
     - New function called "prop.var" which calculates the proportion
       of variance explained by a locus given the cross type, effect,
       and error variance.
0.85 -> 0.90
     - Added the functions to calculate genome-wide thresholds and
       tail probabilities for genome scans using Poisson approximations.
     - Changed search interval for detectable effect calculation.
     - Renamed bio.var env.var in powercalc(), and error.var().
     - Changed genome length argument to G from L in thresh() and tail.prob().
     - Changed the units to centiMorgans from Morgans for genome length 
       and marker spacing arguments.
0.90 -> 0.91
     - Partial argument matching no longer allowed in optimize, optim, 
       uniroot, nlm, and integrate.  Changed functions to reflect that.
	https://stat.ethz.ch/pipermail/r-devel/2007-May/045791.html
0.91 -> 0.92
     - Add the ci.length function for calculating confidence interval
       lengths
     - Replaced optim by optimze in optspacing function for the 1-dim
       optimization; works better
     - Added functions for selective phenotyping (from Brian Yandell)