Merge branch 'master' of github.com:hadley/tidyr

Author: hadley

.travis.yml

@@ -1,5 +1,16 @@
-language: R
+# R for travis: see documentation at https://docs.travis-ci.com/user/languages/r
+
+language: r
 cache: packages
+r:
+  - oldrel
+  - release
+  - devel
 
 after_success:
   - Rscript -e 'covr::codecov()'
+
+notifications:
+  email:
+    on_success: change
+    on_failure: change