Added automatic testing of snip-tags

.gitlab-ci.yml

tests/demo1/ex1.py

tests/demo1/tree.py

tests/demo1_correct/code/ex1.py

tests/demo1_correct/code/tree.py

tests/demo1_correct/output/tree_a.py

tests/demo1_correct/output/tree_a.shell

tests/demo1_correct/output/tree_a.txt

tests/demo1_correct/output/tree_b.shell

tests/demo1_correct/output/tree_myfile.py

tests/demo1_tmp/code/ex1.py

tests/demo1_tmp/code/tree.py

tests/demo1_tmp/output/tree_a.py

tests/demo1_tmp/output/tree_a.shell

tests/demo1_tmp/output/tree_a.txt

tests/demo1_tmp/output/tree_b.shell

tests/demo1_tmp/output/tree_myfile.py

tests/setup_test_files.py

tests/test_python.py