Add coveralls support

Author: wdv4758h

.travis.yml

@@ -18,7 +18,7 @@ matrix:
 
 install:
     - "pip install -U pip"
-    - "pip install -U pytest pytest-runner flake8 mypy-lang"
+    - "pip install -U pytest pytest-runner flake8 mypy-lang coveralls"
     - "pip install ."
     - "pip freeze"
 
@@ -27,5 +27,8 @@ script:
     - python setup.py flake8 || true
     - mypy everywhere
 
+after_success:
+    - coveralls
+
 notifications:
     email: false