Remove unused .travis.yml file

.travis.yml

-language: python
-python: "3.6"
-notifications:
-  email: true
-install:
-  - pip install -r build/requirements.txt
-before_script:
-  # stop the build if there are Python syntax errors or undefined names
-  - flake8 . --count --select=E901,E999,F821,F822,F823 --show-source --statistics
-  # exit-zero treats all errors as warnings.  The GitHub editor is 127 chars wide
-  - flake8 . --count --exit-zero --max-complexity=10 --max-line-length=127 --statistics
-  - cd build
-script:
-  - ./main.sh
-