Revert "sudo-less Travis"

This reverts commit 71666c6.

.travis.yml

@@ -1,45 +1,11 @@
-# .travis.yml using container-based infrastructure
-
-# use c as catch-all language
 language: c
-
-# use containers
-sudo: false
-
-# install R: use r-packages-precise (https://cran.r-project.org/bin/linux/ubuntu/precise/)
-# as source which is white listed (https://github.com/travis-ci/apt-source-whitelist/)
-addons:
-  apt:
-    sources:
-    - r-packages-precise
-    packages:
-    - r-base-dev
-    - r-recommended
-    - r-cran-devtools
-    - r-cran-testthat
-    - pandoc
-
-# cache local R libraries directory:
-cache:
-  directories:
-    - ~/Rlib
+sudo: required
 
 before_install:
   - curl -OL http://raw.github.com/craigcitro/r-travis/master/scripts/travis-tool.sh
   - chmod 755 ./travis-tool.sh
   - ./travis-tool.sh bootstrap
-
-# install the package and dependencies:
-# - create directory for R libraries (if not already exists)
-# - create .Renviron with location of R libraries
-# - define R repository in .Rprofile
-# - update all installed packages
-# - install covr if not already installed
-# - install package with dependencies
 install:
-  - mkdir -p ~/Rlib
-  - echo 'R_LIBS=~/Rlib' > .Renviron
-  - Rscript -e 'update.packages(ask = FALSE, instlib = "~/Rlib")'
   - ./travis-tool.sh install_github jimhester/covr
   - ./travis-tool.sh install_deps
 
@@ -48,11 +14,9 @@ script: ./travis-tool.sh run_tests
 after_failure:
   - ./travis-tool.sh dump_logs
 
-# report coverage rate to codecov
 after_success:
   - Rscript -e 'covr::codecov()'
 
-# send e-mails if stuff changes
 notifications:
   email:
     on_success: change