Merge pull request facebookarchive#259 from zlandau/travisicon

Limit travis status in README to the master branch

Author: fpotter

README.md

@@ -4,7 +4,7 @@ __xctool__ is a replacement for Apple's __xcodebuild__ that makes it
 easier to build and test iOS and Mac products.  It's especially helpful
 for continuous integration.
 
-[![Build Status](https://travis-ci.org/facebook/xctool.png)](https://travis-ci.org/facebook/xctool)
+[![Build Status](https://travis-ci.org/facebook/xctool.png?branch=master)](https://travis-ci.org/facebook/xctool)
 
 [ [Features](#features) • [Requirements](#requirements) • [Usage](#usage)
 • [Continuous Integration](#continuous-integration)