Announcing secr 3.2.0

[murray.efford]

secr 3.2.0 now on CRAN has some significant improvements for the calculation of density across replicated detector clusters (see ?derivednj etc.). make.systematic() has some new options. The summary method for capthist objects optionally reports on movements (moves = TRUE). Other changes address minor frustrations: mixture models now work when the first detector is unused on the first occasion; plot.traps() can add gridlines to an existing plot etc. See https://CRAN.R-project.org/package=secr.