Only test Lua in 2.7 and 3.5

Author: beamerblvd

.travis.yml

@@ -11,7 +11,9 @@ python:
 - '3.4'
 - pypy
 - pypy3
-install: pip install .[lua]
+install:
+- pip install .
+- if [[ $TRAVIS_PYTHON_VERSION == 2.7 ]] || [[ $TRAVIS_PYTHON_VERSION == 3.4 ]]; then pip install .[lua]; fi
 script: python setup.py nosetests
 deploy:
   provider: pypi