Explicitly emitting the current Python version before testing

Author: pavel-kirienko

.travis.yml

@@ -15,6 +15,7 @@ before_script:
   - pip install coveralls  # Intentionally removed from requirements.txt because it's only useful in the CI environment
 
 script:
+  - python --version
   - ./test.sh
   - coveralls  # Publish the coverage stats online.
   - git clone https://github.com/UAVCAN/dsdl --branch=uavcan-v1.0 dsdl-test  # TODO: Switch to master once v1.0 is merged