keep travis only to build on gh page

.travis.yml

@@ -17,19 +17,16 @@ repos:
 before_install:
   - "curl https://xran.yihui.org/.gitconfig -o ~/.gitconfig"
   - Rscript -e "update.packages(.libPaths()[1], ask = FALSE)"
-  - export BUILD_ALL="$(git log --format=%B --no-merges -n 1 | grep -E "\[build all\]")"
 
 jobs:
   include:
-    - r: oldrel
     - r: release
       before_script:
         - "[ -x \"$HOME/bin/phantomjs\" ] || Rscript -e \"webshot::install_phantomjs()\""
         - R CMD INSTALL .
         - cd inst/examples
-        - "[ ! -z \"$BUILD_ALL\" ] && make all || make gitbook"
+        - make gitbook
         - cd ../..
       after_success:
         - "(curl https://xran.yihui.org/r-xran | bash)"
         - cd inst/examples; ./deploy_github
-    - r: devel