message: Add a section about running the benchmarks with python. Also renamed so that and have different titles
diff: -# Benchmarks
  +# Defining and Running Benchmarks
  This guide contains instructions for defining and running a TensorFlow benchmark. These benchmarks store output in [TestResults](https://github.com/tensorflow/tensorflow/blob/master/tensorflow/core/util/test_log.proto) format. If these benchmarks are added to TensorFlow github repo, then we will run them daily with our continuous build and display a graph on our dashboard: https://benchmarks-dot-tensorflow-testing.appspot.com/.
  @@ -52,6 +52,19 @@ Key points to note in the example above:
  * Benchmark method calls `report_benchmark` to report the metric value.
  +## Running with Python
  +
  +Use the `--benchmarks` flag to run the benchmark with python. A [BenchmarkEntries](https://github.com/tensorflow/tensorflow/tree/master/tensorflow/core/util/test_log.proto) proto will be printed.
  +
  +```
  +python sample_benchmark.py --benchmarks=SampleBenchmark
  +```
  +
  +Setting the flag as `--benchmarks=.` or `--benchmarks=all` would work as well.
  +
  +(Please ensure that Tensorflow is installed to successfully import the package in the line `import tensorflow as tf`. For installation instructions, see [Installing TensorFlow](https://www.tensorflow.org/install/). This step is not necessary when running with bazel.)
  +
  +
  ## Adding a `bazel` Target
  We have a special target called `tf_py_logged_benchmark` for benchmarks defined under TensorFlow github repo. `tf_py_logged_benchmark` should wrap around a regular `py_test` target. Running a `tf_py_logged_benchmark` would print a [TestResults](https://github.com/tensorflow/tensorflow/blob/master/tensorflow/core/util/test_log.proto) proto. Defining a `tf_py_logged_benchmark` also lets us run it with TensorFlow continuous build.
  