visualization code docs / bugfixes (#701)

* viz docs

* writing vizualization docs

* documenting plot_util

* docstrings in plot_util

* autopep8 and flake8

* spelling (using default vim spellchecker and ingoring things like dataframe, docstring and etc)

* rephrased viz.md a little bit

README.md

@@ -109,17 +109,9 @@ python -m baselines.run --alg=ppo2 --env=PongNoFrameskip-v4 --num_timesteps=0 --
 
 *NOTE:* At the moment Mujoco training uses VecNormalize wrapper for the environment which is not being saved correctly; so loading the models trained on Mujoco will not work well if the environment is recreated. If necessary, you can work around that by replacing RunningMeanStd by TfRunningMeanStd in [baselines/common/vec_env/vec_normalize.py](baselines/common/vec_env/vec_normalize.py#L12). This way, mean and std of environment normalizing wrapper will be saved in tensorflow variables and included in the model file; however, training is slower that way - hence not including it by default
 
+## Loading and vizualizing learning curves and other training metrics
+See [here](docs/viz/viz.md) for instructions on how to load and display the training data. 
 
-## Using baselines with TensorBoard
-Baselines logger can save data in the TensorBoard format. To do so, set environment variables `OPENAI_LOG_FORMAT` and `OPENAI_LOGDIR`:
-```bash
-export OPENAI_LOG_FORMAT='stdout,log,csv,tensorboard' # formats are comma-separated, but for tensorboard you only really need the last one
-export OPENAI_LOGDIR=path/to/tensorboard/data
-```
-And you can now start TensorBoard with:
-```bash
-tensorboard --logdir=$OPENAI_LOGDIR
-```
 ## Subpackages
 
 - [A2C](baselines/a2c)