Merge branch 'joss' into 'master'

.gitlab-ci.yml

CMakeLists.txt

cmake/CoinUtils/coin_utils_make_install.sh

cmake/coin-Clp/clp_make_install.sh

codemeta.json

docs/cpp_api/FeatureCreation.rst

docs/cpp_api/node.rst

docs/quick_start/Installation.md

docs/quick_start/code_ref.md

docs/tutorial/0_intro.md

docs/tutorial/1_command_line.md

docs/tutorial/2_python.md

docs/tutorial/3_classification.md

docs/tutorial/classification/c_1.png

docs/tutorial/classification/c_10.png

docs/tutorial/classification/c_100.png

docs/tutorial/classification/c_1000.png

docs/tutorial/classification/data_class.csv

docs/tutorial/classification/sisso.json

docs/tutorial/classification/sissopp.png