install casperjs and slimerjs on travis

.travis.yml

@@ -1,6 +1,18 @@
 language: node_js
 node_js:
   - "0.10"
+env:
+  - SLIMERJSLAUNCHER=$(which firefox) DISPLAY=:99.0 PATH=$TRAVIS_BUILD_DIR/slimerjs:$PATH
+addons:
+  firefox: "31.0"
+before_script:
+  - "sh -e /etc/init.d/xvfb start"
+  - "echo 'Installing Slimer'"
+  - "wget http://download.slimerjs.org/releases/0.9.1/slimerjs-0.9.1.zip"
+  - "unzip slimerjs-0.9.1.zip"
+  - "mv slimerjs-0.9.1 ./slimerjs"
+  - npm install -g casperjs
 script:
+  - casperjs
   - cd java && make && cd ..
   - cd tests && make && cd ..