adding three exercises, turbie package

.gitlab-ci.yml

docs/source/index.rst

docs/source/turbie/1-definition.ipynb

docs/source/turbie/2-loading-plotting.ipynb

docs/source/turbie/3-psd.ipynb

docs/source/turbie/CT.txt

docs/source/turbie/figures/1-diagram.png

docs/source/turbie/figures/2-plot-results.png

docs/source/turbie/index.rst

docs/source/turbie/res_12_ms_TI_0.1.txt

docs/source/turbie/turbie_parameters.txt

turbie/setup.py

turbie/turbie/__init__.py