Use the new containerized build system at Travis CI.

.travis.yml

@@ -1,6 +1,12 @@
+sudo: false
 language: python
 python:
   - "2.6"
+env:
+  - PIP_DOWNLOAD_CACHE="pip_cache"
+cache:
+  directories:
+    - pip_cache
 before_script:
   - flake8 news
   - mysql -e 'create database basket;'
@@ -9,10 +15,10 @@ script: coverage run manage.py test news
 before_install:
   - git submodule update --init --recursive
 install:
-  - pip install -r requirements/compiled.txt -r requirements/dev.txt --use-mirrors
+  - pip install -r requirements/compiled.txt -r requirements/dev.txt
 after_success:
   # Report coverage results to coveralls.io
-  - pip install coveralls --use-mirrors
+  - pip install coveralls
   - coveralls
 notifications:
   irc: