rust 1.2.0

New features

Packages Rcpp (https://CRAN.R-project.org/package=Rcpp) and RcppArmadillo (https://CRAN.R-project.org/package=RcppArmadillo) to speed up the computations if the user provides a C++ function to evaluate their target log-density.
New functions: ru_rcpp, find_lambda_rcpp and find_lambda_one_d_rcpp.
New vignette. "Rusting faster: Simulation using Rcpp".

Bug fixed in plot.ru(): previously plot.ru() failed when d > 2 and no axis label names were provided.
Bug fixed in plot.ru : previously, in the d = 2 case, providing the graphical parameter col produced an error because col = 8 was hard-coded in a call to points. Now the extra argument points_par enables the user to provide a list of arguments to points.
"using pairs()" removed from the last sentence Description of plot.ru() because pairs() is not used when d > 2, rather a single plot is produced for each pair of variables.
Obsolete function rho_to_theta() removed from function ru in ru_sampling.R.
If the user calls ru (or ru_rcpp) with trans = "user" but doesn't supply phi_to_theta then an error is returned.
plot.ru edited to avoid warning message that occurred in the d=1 case when breaks was supplied as an argument.
The functions rgpd, gpd_sum_stats, gpd_init and gpd_logpost are now exported.