Remove python 3.6 from builds

Author: pksohn

.travis.yml

@@ -3,7 +3,6 @@ sudo: false
 python:
 - '2.7'
 - '3.5'
-- '3.6'
 
 install:
 - if [[ "$TRAVIS_PYTHON_VERSION" == "2.7" ]]; then wget http://repo.continuum.io/miniconda/Miniconda-latest-Linux-x86_64.sh