Upgrade selenium and use geckodriver to run firefox tests.

The current version of selenium, firefox and 16.04 don't play well together.

.travis.yml

@@ -3,6 +3,9 @@ language: python
 python:
     - "3.5"
 
+addons:
+  firefox: "latest"
+
 services:
   - docker
 
@@ -19,6 +22,7 @@ before_install:
     - "export DISPLAY=:99.0"
     - "sh -e /etc/init.d/xvfb start"
     - "export DJANGO_SETTINGS_MODULE=course_discovery.settings.test"
+    - export PATH=$PATH:$PWD/node_modules/.bin
     - docker run --detach  --publish 9200:9200 --publish 9300:9300 elasticsearch:1.5.2
 
 install:

package.json

@@ -11,6 +11,7 @@
   },
   "devDependencies": {
     "gulp": "^3.9.1",
-    "gulp-jscs": "4.0.0"
+    "gulp-jscs": "4.0.0",
+    "geckodriver": "1.2.0"
   }
 }

requirements/test.txt

@@ -13,5 +13,5 @@ nose-exclude==0.5.0
 nose-ignore-docstring==0.2
 pep8==1.7.0
 responses==0.5.1
-selenium==2.53.6
+selenium==3.0.2
 testfixtures==4.13.1