simplify .travis.yaml from unnecessary options

removes site-packages, causes errors on most pythons now
add python 3.4, horay.
don't install python and python3-yaml,
  installing coveralls is sufficient

.travis.yml

@@ -5,22 +5,19 @@ python:
   - 2.7
   - 3.2
   - 3.3
+  - 3.4
   - pypy
 
-virtualenv:
-  system_site_packages: true
-
-before_install:
-  - sudo apt-get install python-yaml python3-yaml
 install:
   - export PYTHONIOENCODING=UTF8
   - python setup.py install
-  - pip install coveralls --use-mirrors
+  - pip install coveralls
 
 before_script:
   - source test.env
+
 script:
-  - coverage run tools/testall.py
+  - coverage run -p tools/testall.py
 
 after_success:
   - coverage combine