update latex packages

Author: yihui

.travis.yml

@@ -40,6 +40,7 @@ addons:
 # install dependencies
 install:
   - "[ ! -d ~/bin ] && mkdir ~/bin || true"
+  - rm -r ~/texlive
   - "wget -q -O - https://github.com/yihui/crandalf/raw/master/inst/scripts/install-texlive | bash"
   - "wget -q -O - https://github.com/yihui/crandalf/raw/master/inst/scripts/install-pandoc | bash"
   - "wget -q -O - http://yihui.name/xran/r-config | bash"