add documentation and notebooks

_notebooks/elements/HornsrevSite.ipynb

_notebooks/elements/IEA37Site.ipynb

_notebooks/elements/IEA37Turbine.ipynb

_notebooks/elements/IntroWindTurbines.ipynb

_notebooks/elements/V80.ipynb

_notebooks/elements/WindTurbines.ipynb

_notebooks/elements/doc_setup.ipynb

_notebooks/elements/fuga.ipynb

_notebooks/elements/noj.ipynb

_notebooks/elements/tutorial_setup.ipynb

_notebooks/make_notebooks.py

_notebooks/templates/windturbines.ipynb

docs/notebooks/HornsrevSite.ipynb

docs/notebooks/IEA37Site.ipynb

docs/notebooks/IEA37Turbine.ipynb

docs/notebooks/V80.ipynb

docs/notebooks/fuga.ipynb

docs/notebooks/noj.ipynb

docs/source/_static/logo.png

docs/source/reference_guide.rst