moved slides to older times

.gitmodules

slides_2019/base_X.md

slides_2019/delaunay.md

slides_2019/ligne_commande.md

slides_2019/make.md

slides_2019/oral.md

slides_2019/pointeurs_avances.md

slides_2019/strings.md

slides_2019/tests_assertions.md

slides_2020/.gitignore

slides_2020/Makefile

slides_2020/base_1.md

slides_2020/base_2.md

slides_2020/base_3.md

slides_2020/base_4.md

slides_2020/base_5.md

slides_2020/base_6.md

slides_2020/base_7.md

slides_2020/base_8.md

slides_2020/bst.md