Nuke Travis python 3.1 testing

Python 3.1 is unsuported by Travis-ci [1], so this change removes it.

[1]: http://about.travis-ci.org/docs/user/ci-environment/#Python-VM-images

Author: dmcdougall

.travis.yml

@@ -3,15 +3,14 @@ language: python
 python:
   - 2.6
   - 2.7
-  - 3.1
   - 3.2
 
 install:
   - pip install --use-mirrors nose
   # This is a workaround to install numpy with the version of
   # virtualenv in Travis.  If that is updated in the future, this can
   # be simplified to 'pip install numpy'
-  - 'if [ $TRAVIS_PYTHON_VERSION == "3.2" ] || [ $TRAVIS_PYTHON_VERSION == "3.1" ]; then pip install https://github.com/y-p/numpy/archive/1.6.2_with_travis_fix.tar.gz; fi'
+  - 'if [ $TRAVIS_PYTHON_VERSION == "3.2" ]; then pip install https://github.com/y-p/numpy/archive/1.6.2_with_travis_fix.tar.gz; fi'
   - 'if [ ${TRAVIS_PYTHON_VERSION:0:1} == "2" ]; then pip install numpy; fi' # should be nop if pre-installed
   - if [[ $TRAVIS_PYTHON_VERSION == '2.'* ]]; then pip install --use-mirrors PIL; fi
   - python setup.py install