docs update

docs/api/EngineeringWindFarmModels.rst

docs/api/Site.rst

docs/api/WindTurbines.rst

docs/index.rst

docs/install_python.rst

docs/installation.rst

docs/notebooks/ChangeLog.ipynb

docs/notebooks/EngineeringWindFarmModels.ipynb

docs/notebooks/Introduction.ipynb

docs/notebooks/Optimization.ipynb

docs/notebooks/Overview.ipynb

docs/notebooks/Publications.ipynb

docs/notebooks/Quickstart.ipynb

docs/notebooks/RunWindFarmSimulation.ipynb

docs/notebooks/Site.ipynb

docs/notebooks/WindTurbines.ipynb

docs/notebooks/YawMisalignment.ipynb

docs/notebooks/exercises/CombineModels.ipynb

docs/notebooks/exercises/Improve_layout.ipynb

docs/notebooks/exercises/Validation.ipynb