Merge pull request #813 from lilleswing/yapf17

- conda config --add channels http://conda.binstar.org/omnia

- bash scripts/install_deepchem_conda.sh deepchem

- source activate deepchem

- pip install yapf==0.16.2

- pip install yapf==0.17.0

- pip install coveralls

- python setup.py install

script:

DeepChem uses [yapf](https://github.com/google/yapf) to autoformat code.

``` bash

pip install yapf==0.16.2

pip install yapf==0.17.0

cd <git_root>

yapf -i <python_files changed>

```

    dim = 2

    batch_size = 10

    mean_tensor = np.random.rand(dim)

    std_tensor = np.random.rand(

        1,)

    std_tensor = np.random.rand(1,)

    with self.test_session() as sess:

      mean_tensor = tf.convert_to_tensor(mean_tensor, dtype=tf.float32)

      std_tensor = tf.convert_to_tensor(std_tensor, dtype=tf.float32)