Activate Gitlab CI
This MR activates Gitlab CI for this repository. The main addition is the .gitlab-ci.yml file which activates the CI. I also created a ci/
folder which contains two SuperCollider scripts: one that installs SATIE and its dependencies, the other which runs a series of tests. The latter will need to be updated when new tests are written so that they get included in the CI.
More tests are needed. This will be done in subsequent MRs.