Fix Travis build

continuous_integration/install.sh

@@ -29,7 +29,7 @@ if [[ "$DISTRIB" == "conda" ]]; then
     # Configure the conda environment and put it in the path using the
     # provided versions
     conda create -n testenv --yes python=$PYTHON_VERSION pip nose mock \
-        numpy=$NUMPY_VERSION matplotlib
+        numpy=$NUMPY_VERSION matplotlib pillow
     source activate testenv
 
 
@@ -37,11 +37,9 @@ elif [[ "$DISTRIB" == "ubuntu" ]]; then
     # Use standard ubuntu packages in their default version
     virtualenv --system-site-packages testvenv
     source testvenv/bin/activate
-    pip install nose mock matplotlib
+    pip install nose mock matplotlib pillow
 fi
 
-pip install -r requirements.txt
-
 python --version
 python -c "import numpy; print('numpy %s' % numpy.__version__)"
 python setup.py build_ext --inplace