Merge branch 'pkgdown' into 'master'

.Rbuildignore

.gitignore

README.md

docs/404.html

docs/LICENSE-text.html

docs/android-icon-144x144.png

docs/android-icon-192x192.png

docs/android-icon-36x36.png

docs/android-icon-48x48.png

docs/android-icon-72x72.png

docs/android-icon-96x96.png

docs/apple-icon-114x114.png

docs/apple-icon-120x120.png

docs/apple-icon-144x144.png

docs/apple-icon-152x152.png

docs/apple-icon-180x180.png

docs/apple-icon-57x57.png

docs/apple-icon-60x60.png

docs/apple-icon-72x72.png

docs/apple-icon-76x76.png