update travis to install package deps

Author: raghakot

.travis.yml

@@ -34,18 +34,13 @@ install:
   - conda create -q -n test-environment python=$TRAVIS_PYTHON_VERSION numpy pytest pytest-pep8 pytest-cov matplotlib
   - source activate test-environment
   - pip install git+git://github.com/Theano/Theano.git
-  - pip install keras
-
-  # install PIL for preprocessing tests
-  - if [[ "$TRAVIS_PYTHON_VERSION" == "2.7" ]]; then
-      conda install pil;
-    elif [[ "$TRAVIS_PYTHON_VERSION" == "3.5" ]]; then
-      conda install Pillow;
-    fi
 
   # install TensorFlow
   - pip install tensorflow
 
+  # Install package and test requirements.
+  - pip install -e .[tests]
+
 script:
   # run keras backend init to initialize backend config
   - python -c "import keras.backend"