added python 3.6 test

Author: lh3

Diff for: .travis.yml

@@ -14,3 +14,7 @@ matrix:
       python: "3.5"
       before_install: pip install cython
       script: python setup.py build_ext
+    - language: python
+      python: "3.6"
+      before_install: pip install cython
+      script: python setup.py build_ext

Diff for: README.md

@@ -1,5 +1,6 @@
 [![Release](https://img.shields.io/badge/Release-v2.1.1-blue.svg?style=flat-square)](https://github.com/lh3/minimap2/releases)
 [![BioConda](https://img.shields.io/conda/vn/bioconda/minimap2.svg?style=flat-square)](https://anaconda.org/bioconda/minimap2)
+[![PyPI](https://img.shields.io/pypi/v/mappy.svg?style=flat-square)](https://pypi.python.org/pypi/mappy)
 [![License](https://img.shields.io/badge/License-MIT-blue.svg?style=flat-square)](LICENSE.txt)
 [![Build Status](https://travis-ci.org/lh3/minimap2.svg?branch=master)](https://travis-ci.org/lh3/minimap2)
 ## Getting Started