tests updated, readme updated

.gitlab-ci.yml

@@ -54,4 +54,4 @@ test_load:
       - pip install --upgrade pip
       - pip install .
     script:
-      - python -c 'import plwn; print(plwn.load_default().lexical_unit("pies", plwn.PoS.noun_pl, 2).definition)'
+      - python -c 'import plwn; plwn.download(); print(plwn.load("default_model").lexical_unit("pies", plwn.PoS.noun_pl, 2).definition)'