Fix virtualenv in travis

.travis.yml

@@ -2,25 +2,20 @@ sudo: required
 
 dist: trusty
 
-language: python
-
-python:
-  - '2.7'
+language: generic
 
 before_install:
+  - sudo -H apt-get install -qq -y python-minimal
   - sudo -H apt-get install -qq -y python-matplotlib
-  - sudo -H apt-get install -qq -y python-nose
   - sudo -H apt-get install -qq -y python-numpy
   - sudo -H apt-get install -qq -y python-qt4
   - sudo -H apt-get install -qq -y pyqt4-dev-tools
   - sudo -H apt-get install -qq -y python-scipy
   - sudo -H apt-get install -qq -y python-skimage
-  # - pip install flake8 hacking
-  # - flake8 .
 
 install:
   - sudo -H python setup.py install
 
 script:
-  - sudo -H pip install matplotlib  # FIXME
+  - sudo -H apt-get install -qq -y python-nose
   - nosetests tests