travis: fix tests

- set SHELL=zsh
 - cd back for ZSH=5
 - fix/improve autoenv.plugin.zsh: no dirname, use ${0:h}

.travis.yml

@@ -14,8 +14,9 @@ env:
 
 install:
   - if [ "$ZSH" = 4 ]; then sudo apt-get install zsh; fi
-  - if [ "$ZSH" = 5 ]; then wget http://downloads.sourceforge.net/project/zsh/zsh/5.0.7/zsh-5.0.7.tar.bz2; tar xf zsh-5.0.7.tar.bz2; cd zsh-5.0.7; ./configure && sudo make && sudo make install; fi
+  - if [ "$ZSH" = 5 ]; then wget http://downloads.sourceforge.net/project/zsh/zsh/5.0.7/zsh-5.0.7.tar.bz2; tar xf zsh-5.0.7.tar.bz2; cd zsh-5.0.7; ./configure && sudo make && sudo make install; cd ..; fi
   - pip install cram
+  - export SHELL=zsh
 script:
   - zsh --version
   - make test

autoenv.plugin.zsh

@@ -1 +1 @@
-. $(dirname $0)/autoenv.zsh
+. ${0:h}/autoenv.zsh