Revert "Remove Travis badge"

This reverts commit ac90e0e9398be7447d6a300c3c77c7dba295df48.

README.md

@@ -2,7 +2,7 @@ Fig
 ===
 
 <!--hide-on-homepage-->
-<!--[![Build Status](https://travis-ci.org/orchardup/fig.png?branch=master)](https://travis-ci.org/orchardup/fig)-->
+[![Build Status](https://travis-ci.org/orchardup/fig.png?branch=master)](https://travis-ci.org/orchardup/fig)
 [![PyPI version](https://badge.fury.io/py/fig.png)](http://badge.fury.io/py/fig)
 <!--/hide-on-homepage-->