Merge branch 'master' into core-updates

gnu: r: Update to 3.3.1.

* gnu/packages/statistics.scm (r): Update to 3.3.1.

gnu: r-matrixstats: Update to 0.51.0.

* gnu/packages/statistics.scm (r-matrixstats): Update to 0.51.0.

gnu: r-r-utils: Update to 2.4.0.

* gnu/packages/statistics.scm (r-r-utils): Update to 2.4.0.

gnu: r-irlba: Update to 2.1.2.

* gnu/packages/statistics.scm (r-irlba): Update to 2.1.2.

gnu: r-codetools: Update to 0.2-15.

* gnu/packages/statistics.scm (r-codetools): Update to 0.2-15.

gnu: r-snow: Update to 0.4-2.

* gnu/packages/statistics.scm (r-snow): Update to 0.4-2.

gnu: r-backports: Update to 1.0.4.

* gnu/packages/statistics.scm (r-backports): Update to 1.0.4.

gnu: r-foreign: Update to 0.8-67.

* gnu/packages/statistics.scm (r-foreign): Update to 0.8-67.

gnu: r-cluster: Update to 2.0.5.

* gnu/packages/statistics.scm (r-cluster): Update to 2.0.5.

gnu: r-acepack: Update to 1.4.0.

* gnu/packages/statistics.scm (r-acepack): Update to 1.4.0.

gnu: r-r6: Update to 2.2.0.

* gnu/packages/statistics.scm (r-r6): Update to 2.2.0.

gnu: r-evaluate: Update to 0.10.

* gnu/packages/statistics.scm (r-evaluate): Update to 0.10.

gnu: r-reshape2: Update to 1.4.2.

* gnu/packages/statistics.scm (r-reshape2): Update to 1.4.2.

gnu: r-stringi: Update to 1.1.2.

* gnu/packages/statistics.scm (r-stringi): Update to 1.1.2.

gnu: r-matrix: Update to 1.2-7.1.

* gnu/packages/statistics.scm (r-matrix): Update to 1.2-7.1.

gnu: r-colorspace: Update to 1.2-7.

* gnu/packages/statistics.scm (r-colorspace): Update to 1.2-7.

gnu: r-rcpparmadillo: Update to 0.7.500.0.0.

* gnu/packages/maths.scm (armadillo-for-rcpparmadillo): Update to
7.500.0.
* gnu/packages/statistics.scm (r-rcpparmadillo): Update to 0.7.500.0.0.

gnu: r-rmarkdown: Update to 1.1.

* gnu/packages/statistics.scm (r-rmarkdown): Update to 1.1.
[propagated-inputs]: Add r-evaluate, r-tibble.

gnu: Add r-kernsmooth.

* gnu/packages/statistics.scm (r-kernsmooth): New variable.