Added travis status to README

Author: ryanuber

README.md

@@ -3,6 +3,8 @@ Columnize
 
 Easy column-formatted output for golang
 
+[![Build Status](https://travis-ci.org/ryanuber/columnize.png)](https://travis-ci.org/ryanuber/columnize)
+
 Columnize is a really small Go package that makes building CLI's a little bit
 easier. In some CLI designs, you want to output a number similar items in a
 human-readable way with nicely aligned columns. However, figuring out how wide