Have Travis enforce 100% coverage

Author: adamtheturtle

.travis.yml

@@ -13,6 +13,6 @@ install:
 cache: pip
 script:
 - make lint
-- pytest -vvv --exitfirst tests/ --cov src --cov tests
+- pytest -vvv --exitfirst tests/ --cov-fail-under 100 --cov src --cov tests
 after_success:
 - codecov