Fix travis setup

.travis.yml

@@ -1,8 +1,14 @@
 language: shell
-before_install:
-  - sudo apt-get update
-install:
-  - sudo apt-get install zsh
-script: make --debug=b test
+sudo: false
+env:
+  - EMACS=emacs24
+addons:
+  apt:
+    sources:
+      - cassou-emacs
+    package:
+      - emacs24
+      - zsh
+script: make --debug=b test emacs=$EMACS
 notifications:
   email: 8slashes+travis-ci@gmail.com