TensorFlow: Initial steps towards python3 support, some documentation bug fixes -- reindents to 2 for some of the files to match our internal requirements.
TensorFlow: Initial steps towards python3 support, some documentation
bug fixes -- reindents to 2 for some of the files to match our internal
requirements.

Thanks to Martin Andrews for the basic_usage.md suggested fix via
Gerrit.

Base CL: 107394029

shakedel/tensorboard,tensorflow/tensorboard,francoisluus/tensorboard-supervise,agrubb/tensorboard,shakedel/tensorboard,qiuminxu/tensorboard,qiuminxu/tensorboard,qiuminxu/tensorboard,tensorflow/tensorboard,ioeric/tensorboard,francoisluus/tensorboard-supervise,ioeric/tensorboard,shakedel/tensorboard,qiuminxu/tensorboard,agrubb/tensorboard,agrubb/tensorboard,francoisluus/tensorboard-supervise,agrubb/tensorboard,agrubb/tensorboard,tensorflow/tensorboard,shakedel/tensorboard,francoisluus/tensorboard-supervise,ioeric/tensorboard,ioeric/tensorboard,tensorflow/tensorboard,agrubb/tensorboard,tensorflow/tensorboard,tensorflow/tensorboard,shakedel/tensorboard,shakedel/tensorboard,ioeric/tensorboard,ioeric/tensorboard,qiuminxu/tensorboard,francoisluus/tensorboard-supervise,tensorflow/tensorboard,francoisluus/tensorboard-supervise,qiuminxu/tensorboard