Add the missed unit tests on "lang ui".
Fixing the label provider for passing unit tests.
Fixing the quick fix provider for passing the unit tests.
Add the missed unit tests for 'io.sarl.lang'.
Add missed unit tests for 'io.sarl.lang.ui'.
Adding error messages in the quickfix unit tests.
Enable UI unit tests with the Tycho Maven plugin.
Add unit tests for the Eclipse outline.