distr6 1.3.0

Major Updates

plot function for plotting the pdf, cdf, survival, quantile, hazard, cumhazard or distr6 objects
lines function for superimposing distr6 plots
qqplot function for comparing distr6 distributions to each other or to other theoretical distributions
Added Extract.VectorDistribution for extracted distributions from inside a VectorDistribution, see the big update below.

decorate now allows users to specify the Decorator as a character as well as supplying the object, this makes it simpler when using distr6 whilst unattached
Big changes (and hopefully final) to the VectorDistribution. Now the VectorDistribution only constructs the internal wrapped distributions when they are extracted or when a function, such as d/p/q/r, are called. This massively reduces a bottleneck in constructing the distribution. Additionally added functions for extracting distributions from inside the VectorDistribution. The only difference that should affect backwards compatibility is that the distribution argument must now be a character and not an object. Custom (i.e. non-SDistribution) distributions should be used in conjunction with the distlist initializer.
Changed the lower bound of positive Sets to .Machine$double.xmin as the previous value of 1.1e-15 was too restrictive
Added skewness, kurtosis, entropy, mgf, cf, and pgf to WeightedDiscrete and Empirical
Added support for custom distributions in VectorDistribution and for CoreStatistics functions as well as support for only one arguments passed to d/p/q/r for fast comparisons between wrapped distributions

Bug fix in WeightedDiscrete distribution variance calculation
Fixed bug in Empirical that was stopping the cdf of the first point in the distribution being evaluated
Fixed bug that allowed invalid parameter values to be set for non-reference parameters
Updated parameter error messages to be more informative
Improved speed and efficiency in Distribution constructor for wrappers