These are CSS/JavaScript changes changes to make navigation in the PySpark API a bit simpler by adding the following to the sidebar:

* Classes
* Functions
* Tags to highlight experimental features

![screen shot 2015-09-02 at 08 50 12](https://cloud.githubusercontent.com/assets/11915197/9634781/301f853a-518b-11e5-8d5c-fda202f6202f.png)

Online example here: https://dl.dropboxusercontent.com/u/20821334/pyspark-api-nav-enhance/pyspark.mllib.html

(The contribution is my original work and that I license the work to the project under the project's open source license)

Author: noelsmith <mail@noelsmith.com>

Closes #8571 from noel-smith/pyspark-api-nav-enhance.